The 9.2.1 installer, or the system itself, appears to have bugs - since installing it on a B&W G3 I've noticed the system seems unstable and no longer wants to talk to my CD-R drive.
One thing for certain, verified by two separate people in different countries, 9.2.1 trashes the Finder's preferences - most noticeable is if you have changed the default folder views, mid-size icons and relative dates are re-instated in list views.