Your tomatoes are already "pushing". Fertilizer will help them do that. In your zone, without freezes, nothing will stop them entirely. In principle, tomatoes are perennials. Blossom drop happens if nighttime temps get below 55F. So if you get a few nights without those low temps, you'll still get fruit. The blossoms are only viable for a few days in the first place. So in your winter climate, you'll probably lose some blossoms, and others will set fruit.

It would depend on the fertilizer used IMO. Why push now for even more greenery with nitrogen? Triggering a new growth spurt will only slow current fruit production if you aren't careful.

Dave

Thank you gentleman.

Dave, I was going to use either phosphorous, potassium instead of nitrogen which from what I understand, puts out green growth

San Diego area here too. I typically fertilize the tomatoes I'm planning on overwintering in September/October when I pull the tomatoes I'm not overwintering. If you haven't fertilized since summer, it can't hurt. Here's hoping we get some good winter BLT tomatoes if nothing else ;)