See below, sort of related.
We'll have to test and make a determination on this one. If people have their own data/experience to share, that would be appreciated too. It's a bit of a hard line to say mid-week "Everyone must be on 1.09", especially if anyone so far has put in a huge effort on 1.08 and won't have time for more laps.
Plus, as @
PASM has found, if you have a 12GB PS3, the total size of GT6 updates alone is too large for that console.
So to update to 1.09 you have to install a larger hard-drive.