Bull.
The DX 9.0b drivers are pretty damn stable for most standard combinations of hardware and software. In this case, the slagging of MS DX is NOT warranted. The b in DirectX 9.0b does not stand for beta.
Try another cause. Look at file corruption, wonky graphics, motherboard or sound card card drivers, or even hardware failure. Any one of these could be causing the issues you describe.
This from someone who's always ever been a proponent of Linux...so you know he hadda be serious
But seriously...he's quite right. The DirectX API been out for long enough now and has garnered enough support such that MS can't just throw something out there in an adhoc fashion...
And yes...the "b" means it has only minor changes since the 9.0a version...not b as in beta...just look at when that was released...July 1st 2003...over a year ago! Been working rock solid for me since I installed it that same day.