I find things like that irritating. "Withstand quakes of up to 9.0." From how far away from the epicenter and how deep is it? Magnitude really says little about the actual ground movement that the building is exposed to. My house has survived dozens of earthquakes over 8.5, just none were nearby.
I'm not sure buildings are even rated like that. They should be rated in peak grand acceleration that they can withstand. That's the actual stress the building would be exposed to. I can see some nuclear powerplants are rated in Gal, 1000 gal being roughly 1g, 980 to be exact. Appears many reactors in japan are designed to shut down at 400, .4G or less. For reference Fukushima was hit by about .3.-.6g. The chch quake in some places was over 2000
I haven't been able to find any ground acceleration readings for wellington though.