Dude,
This is my thoughts, so take it with a grain of salt. Of course it makes sense to seek expert opinions.

Keep in mind 9 Richter scale is just 1.1 level above 7.9R. From the pictures I see cracks only. And the level of earthquake movement at one location in a given radius of say 20 km will be different from another location within that radius, depending upon the distances from the epicenter (and the scientist gives you an instrument's reading or two). I'm not a scientist on earthquake, but my theory is some locations in fact might amplify the movement because the texture and nature of the ground at that location is different from another location. The foundations, elevations etc will matter. Also, as we have seen, if the ground develops cracks, then even the houses might be built for 15 R scale, but the houses will disappear into the, well, "black holes". And there might be margins of errors on predictions.
To make my point, take a few bottles and put them on top of each other, making sure they stand upright. Once all the bottles are upright on their own and stable, push the top bottle off the tower. The bottle will probably be damaged. Now if you use only one bottle on a plane surface, and knock it over with about the same force, very likely the bottle will suffer less damage than the first one.
The first one smashed onto the floor with force far greater than the second one, although the amount of force you used is probably the same in both cases. This is because of transfer of extra potential energy of the top bottle to kinetic energy on top of the energy it got from your push.
In some cases, houses might withstand more than what it was designated to (I'm not sure about such cases but I'd love such engineers), but the reasons will follow similar thinking.
In your case, I'd be happy if there were no casualties.

"Keep in mind 9 Richter scale is just 1.1 level above 7.9R."

Hope you realize that a Richter Scale (RS) is 10-base Logarithmic scale. So 9 RS is more than 10 times 7.9 RS. That's a significant difference, beyond the margin of difference you are referencing. If a house is built for 9 RS, it shouldn't crack at the load-bearing pillars, even when the quake is as shallow as the last one.

@ magdadela

Exactly you are not a scientist of an earthquake as you mentioned 9 richter scale is just 1.1 level above 7.9 richter scale. You are totally unaware of the fact that the amplitude increases 100 times between a level 7 earthquake and a level 9 earthquake. The amount of energy released increases 31.7 times between whole number values.

"I'm not a scientist on earthquake, but my theory is some locations in fact might amplify the movement because the texture and nature of the ground at that location is different from another location."

Really?

So, the difference between 8 and 9 is 10 times amplitude and 31.7 times energy. I can take that. Now how accurate is the instrument?
I remember even the US is adjusting the level from 7.5 to 7.8 and some others are saying 7.9. Right there there is a difference of 2 to 3 times. Were they forecasting something that had already happened looking at the damage or they had instruments on the ground around Gorkha and looking at the table or graphs from the instruments?

My feeling is, none of the engineers in the world will be able to exactly say it will not crack at 7R but will crack at 8R for each house they build. Correct me, but earthquake resistance has some part of statistical nature along with deterministic characters.

GeetMaiDiu,
Yes. I stand by that theory.

Now you are arguing just for the sake of arguing.
Before making a statement, why don't you do a little more study? You are refuting a given premise, you probably should do a little more digging before you refute.

You mentioned "statistics," the difference in magnitude of what was promised (9) is no where close to being statistically insignificant. Sure things don't always work all the time as planned - that is called a failure unless it is within the margin of error. If we were talking about 8.2, maybe I'd say meh. 9 vs 7.9 is pretty big dude.

building does not seem damaged in its core structures. The cracks are on the brick additions on concrete structural frame.

Kiddo
Yes I'm talking about failures too, and for talk's sake; I'm pretty sure so you are.
Do you expect me to think you have the final verdict when you say, "If we were talking about 8.2, maybe I'd say meh. 9 vs 7.9 is pretty big dude." Sorry, it's too early.

On the one hand, the engineers are making when reading the instrument they are saying anywhere from 7.5 to 7.9R. If this science is so accurate, I'm pretty sure the US would not have made a lower prediction of 7.5
Astu

There can be 2 types of issues with Earthquake resistant building showing cracks-

1. Not following the safety code/standards: In Nepal its quite easy to bypass the law and regulations. What I heard from one of the radio is, most high rise in Nepal has approval from the government to follow the regulations but contractors only build with regulation in lower floors and compromise the safety in upper floors, as nobody often followup on safety check. I think that is what happened in Nepal earthquake case. As the earthquake was 7.9 at its core, its impact is even reduced while arriving at Kathmandu.

2. The nature of Earthquake - The seismic waves generated at the time of earthquake fault movement are not all of a uniform character to all buildings. As these waves pass through the earth on their way from the fault to the building site, they are modified by the soil and rock media through which they pass. In simple terms, depending on the earthquake frequency and resonance in respect to the building frequency, toughest building can collapse.

http://imaginationstationtoledo.org/content/2011/03/can-you-build-an-earthquake-proof-building/

Folks
Here is my first ever research on this subject. As a common man, it's hard to believe those pillars would not stand 9.0R, but as you can see they failed at 6.7R

http://www.physicalgeography.net/fundamentals/10m.html

And The equation for energy is

E = 1.74*(10^^(5+1.44*M)) Joules, where M= magnitude in RS

So
e7 = 1.74*(10^^(5+1.44*7)) J
e8 = 1.74(10^^(5+1.44*8)) = 1.74(10^^(5+1.44*7)* 10^^(1.44))

e8/e7 = 10^^(1.44) = 26.54

Correct me if I've made a mistake. Somebody said above it was 31.7 times stronger per unit increment of RS? I'd say close.

The Star Mall building in front of my house is also cracked. Same with City center and these housing. They never made it to last long. Those builders have funneled huge money out to their own pockets.

Yogendra Shrestha took Rs 2 Billion loan from different Banks and hid Rs. 1 Billion of the money in his different loan accounts. It seems he didn't even spend the other Rs. 1 Billion as now the 5 year old building is cracked.

The Banks who loaned him money were supposed to auction the Building to recover their money but central bank didn't allow them and said that Nepal Share Market and Finance which was run by Yogendra will be allowed to sell it. I heard that Nepal Share Market is still running the place making money for Yogendra's cronies after he paid the Maobadi Thulabadas few crore rupees. It was not difficult for him and his cronies as they had stolen Rs 1 Billion already.

No more!

Here's some info on how small RS difference could be ...

http://qz.com/394053/was-the-nepal-earthquake-twice-as-big-as-we-thought/