More than anything, I'm just curious to know if this is even possible, since Plan 9 isn't in the list of GuestOSes on the VirtualBox website.
However, if someone out there has got it working, my specific question: Whenever I try to boot Plan9, either as a live cd or to install inside of VirtualBox, once the GUI loads all I get is a screen of garbage. I think I've tried just about every graphics driver combination at startup - specifically, even 640x480x8 in VESA mode didn't work.
Any suggestions as to how I can load it?