That is messed up, I have been using WMP9 beta for qutie a while now, and never came across this problem. But as long as it fixed it, that is what counts........
I know you can get out the equalizer out and it has a change for speeds, etc.
Click on the mouse looking thing right above the play button..... Then choose settings........show settings.......Then choose the button next to the graphic eqalizer pointing to the right.....That has play speed controls......Not sure if this is how you want to go about doing this, but it might help......