I have BeOS 5... but the PowerPC
Read Me says that it is
BeOS 4.1. This is most likely because it was last updated right after Apple had moved to the G3 and killed off the clones.
As for the question of running it on a 9600... I would think that the main issue is making sure that you have a compatible video card (though the Mach V based systems may have logic board issues... these 9600/8600 systems weren't like any of the PCI Macs that came before them). From what I've been able to gather, the 9500/9600 series shipped with the following video cards:
9500 series (original): ATI Mach 64 with 2 or 4 MB VRAM
9500 series (alternate): IMS TwinTurbo M2 with 2 or 4 MB VRAM
9600 series (200, 200MP, 233): IMS TwinTurbo M4 with 4 MB VRAM
9600 series (300, 350): IMS TwinTurbo M8 with 8 MB VRAM
TwinTurbo based cards were also used in quite a few Power Computing systems, so I would guess that the TwinTurbo based cards would be supported.
Once you start adding in cards past around 1999, you'll most likely have issues with drivers. Be was encouraging their users to move to the Intel platform and away from PowerPC, so I doubt they put any effort into supporting later video cards.
And all that is a guess, as I haven't gotten around to attempting to install BeOS on any of my systems. After I got the CD, I wasn't quite as interested in the BeOS as I was some of my other operating systems. I guess I should attempt to install it on either my PowerTower Pro or my 8500 at some point... just so I know more about it.