I installed OS 9.2.2 using the boot disk available here on an iBook G4 14" and the screen goes black shortly after most of the extensions load. Pressing brightness down (F1) 20-30 times brightens the screen. However, I noticed something curious after I installed OpenBSD 7.1 to another partition: if you do not automatically boot mac os 9, but stop at the OpenFirmware prompt and then type mac-boot, Mac OS 9 fully boots and the screen does not go black!
I have run the following openfirmware commands so that the mac waits at the OpenFirmware prompt for me to choose to boot OS 9 (mac-boot) or OpenBSD (boot hd:,ofwboot)
setenv auto-boot? false
reset-all
I am not recommending anyone install OpenBSD 7.1, but rather stopping the boot process at the OF prompt to mitigate the annoying black screen problem (and save the now precious F1 key from wearing out!).
(OpenBSD 7.1 PPC and I suspect most 32bit linux distros currently have NO Firefox and one is better off using the last Classilla on os 9.)