I dont understand your question.
It seems to be a high end graphics card and if AC runs fine on a G4 TI 128MB 4400 why wouldnt it run on the one you pointed out?
If you ask me it seems overkill for AC. I am using the G6 6800 Ultra and I have no problems in Open GL. Smooth navigation all around a 100Mb AC model.
Instead I would be looking to get the most powerful processor you can get your hands on and not waste your money on a GCard that will collect dust, because you will not have the opportunity to use it to its full potential on AC9.
I am not aware of any GCards that are not compatible. (Unless obviously you are talking on board/shared crap)