If you haven't done it before, run Dxdiag to see what features your card
supports.... (it should support most, if not all)
[Click START, then Run, and just type in dxdiag, and press enter]
It won't hurt your card. None of the versions will. It just
tests/enables/configures features that your card has. It cannot enable
features that your card doesn't have.
DirectX 9 just takes better advantage of what features it does.
Good luck,
-Lawrence in Seattle