As I've stated in another thread that it's not entirely correct that it needs dx9. This is only needed if you want to use the dx9 overlay, that you use usually with shift-tab. Anarchy Online could have been on Steam since late 2003 or early 2004 technically. And many games are dx7 on Steam, they just don't use the overlay. So AO could been on Steam now, or 5 years ago or 10 years ago etc.