Obvs we don't really know that much about our team or - just as importantly - the teams we're playing.
But, on paper anyway, only three or four teams on our schedule have comparable talent, and Kelly's done a pretty good job in recent years of not losing to inferior opponent, the injury-ravaged end of 2014 aside.
That, to me, is why 9-3 seems like a reasonable floor (though, as Insanity said, it's also why USC is often ranked in the top 10 preseason).
But we've got to stay healthy, develop some new leaders on D and keep it simple out there to hide our weak spots (outside backer, safety). None of those things are guaranteed.
OTOH, I'm not worried about the offense at all. Two top-notch QBs. Best stable of RBs I can remember. A very good line. And, while we may not have a Will Fuller or Tyler Eifert-level talent at WR/TE, we've got plenty of guys who can catch the ball. Some of them will emerge.