DX 9.0b is out and ive installed it . it seams like its more driver friendly then the other 2 previous versons . Working ok so far here.
One thing though you cannot uninstall DX9 and go back to dx8.1 with out reformating . i already tried when my pc messed up w dx9.0a .
so unless there's a game that requires dx9 that you want to play I wouldnt mess with something thats working fine. it seams to me that there still working the bugs out of it !