Hi Bellagg,
I think what your supervisor means is that you will probably pass if you submit in October, but that you might walk away with a different outcome i.e. more corrections post viva than you would if you had more time to work on it. I don't think what he's said is bad, it's usual to get "corrections" post viva - a viva outcome is likely to be pass with minor corrections, pass with major corrections, revise and resubmit or fail.
It's extremely rare for someone to get no corrections post viva, it might help if you read your university's guidelines on viva and viva outcomes.
I hope that's helped, good luck with submission!