I unmasked r9 to test it, and right after the usb message, the computer halts. No oopses, just hanging. No way to reach it except powercycling it. I'll see if I can retrieve my .config, but basically it's the same as I used for the r7 ('standard' configuration except XFS, no reiser or ext3), except that I turned off the kernel pre-emption since I heard that it didn't play well with XFS.
gentoo-sources-2.4.19-r9 doesn't have XFS in it... I am therefore confused right now.
That can explain why it dies. :) I just copied the old .config from r7 to r9 and changed enough in the config so I got rid off the preemptive stuff. I never bothered to check if XFS was in or not, as I assumed it was. PEBCAK again, I'm afraid. ;)