Using raft's Bones library, i can animate three ninjas (each around 3000 vertices according to the logs) at max fps (56fps) on a Nexus S (the same thing as a Galaxy S). Considering that the Galaxy S II is even faster, i don't think that you'll run into problems animating a 9k polygon model at a reasonable frame rate. It's hard to guess exactly though. After some experiments that i did on the desktop with using Bones on multiple cores and some fixes that raft has applied to make this possible, you can even use the S II's second core to animate another model in parallel if needed.