It depends on the release, but seven to nine months is plenty to market a major release. I do think it'll be UC4, but whatever it is, I think VGAs is the obvious place to show a teaser.
Drake sleeps on a boat, rocking back and forth, floating in an ocean, camera pulls below the waves revealing Atlantis or whatever. They don't need to show anything really if it's a big franchise, just the confirmation and a teaser, then they can open with it at E3. It's plenty of time.
But yeah, I want to know why shinobi said Fall, if he's got a source for that, because it seems like a strange decision for Sony. It should be a summer release.