Return to V8, update to V9, then use LG Updater tool for VC has messed up both of the Optimus's in my house. I've been experimenting with formatting partitions using zefie's recovery, to no success.
It's my belief that something is getting set in the boot flash upon poweroff that is screwing up the boot.
So in short, do not "Power Off"? Because that was the only instance I had actually powered off was during those instances and I dont feel like going through the entire upgrade process again. (Just did it and got GB up on my phone)