My upgrade was fine, aside from the fact that the installer found that I'd killed PulseAudio with a lead pipe and stuffed it into the fridge with "chmod -x
Unfortunately, 9.10 is dependent on PulseAudio to the point that you can't adjust the volume in Gnome without it. I switched to KDE, and I was happy.
To be safe, I decided to do a new install on my netbook, as the upgrade from 8.10 to 9.04 resulted in a nasty gconf bug that took me a month to track down (leftover 8.10 gconf breaks 9.04). They did finally fix the annoying rt2860 WPA bug. It was a recurring issue on my Eee.
Wishful thinking, I'm afraid.
The Slim simply does not support the OtherOS feature that the original model had. Sony didn't want to put in the resources to write a new hypervisor interface for it.
It's implied that it can be implemented later if demand warrants it.