I haven't seen a thread about iTunes 9.2.1, but according to Redmond Pie, it is safe to update to iTunes 9.2.1 if you are already jailbroken.
I've updated to 9.2.1 and had no issues syncing both my iPhone 3g and iPad wifi.
http://www.redmondpie.com/download-itunes-9.2.1-windows-mac/
I've updated to 9.2.1 and had no issues syncing both my iPhone 3g and iPad wifi.
http://www.redmondpie.com/download-itunes-9.2.1-windows-mac/