I ran into some problems installing 9.10 RC, I also had the same problems with 9.04 so this isn't anything specific to 9.1.
I have a Toshiba L505D-S5992 laptop. It has an Amd Turion II and Ati Radeon 4100 graphics. I had to run the install by selecting the "acpi=off" option from the F6 menu, and I also had to add "acpi=off" to the Grub kernel options to get the installed system to boot. If I don't use "acpi=off", I see a bunch of errors flying by, but the startup dies with the following: '/sbin/modprobe -b acpi:lnxvideo:' unexpected exit with status 0x0009.
While I can get the system up by turning off the acpi option, I'm assuming I'm going to be missing some acpi functionality which might be pretty nice to have on a laptop. Any ideas/suggestions?