Why do you keep saying CM9 doesn't work at all on Vibrant?
I have a CM9 nightly build from 2012-04-17 running on my Vibrant, and haven't even bothered to update since it works so well. I figured I'd help test the CM9 release candidate when it is out, but didn't see it when I looked at their download page after the RC1 announcement.
I admit, the nightly install process was a little clumsy, requiring two attempts because the first often ends with a reboot cycle you have to break by removing the battery and then going back into recovery mode to repeat the wipe/update steps.
I've had at most five crashes in two months with this nightly, where I had to either hold the power button to reboot, or remove the battery when that didn't work. To my knowledge, that's about the same reliability as stock or CM7 for many devices...