No, for me Mathematica 9 continues to be a disaster: I uninstalled 8.0.4, and attempted to install 9.0 using the supposedly "fixed" installer. The result was a BSOD on first starting up Mathematica. I then attempted each of the fixes mentioned in the knowledge base article. The result is that the Mathematica frontend crashes on startup. So this is a no-go: I am unable to install and run Mathematica 9, period.
I might add that the Mathematica installer has had issues with font installation for years. One wonders why it is that every piece of software on the planet can successfully install their fonts on a Windows machine, but Wolfram has trouble figuring this out.