I would think, depending on weather and such, you should be able to. You may (depending on variety)not get many fully mature peppers though. I learned this lesson last year with some of my late ghosts. Ended up with ALOT of green, immature peppers.
If you're willing to overwinter the plants, then go for it! It might be a bit late in the season though to expect any mature fruit from them (depending on what you're looking to grow) but you'll have a head-start for next season. The longer, warmer days this time of year will help the plants come on quicker than if you'd planted them early season too. It you can't overwinter them though, it's probably not worth the effort.
depending on where he is in SoCal he could potentially grow year round, especially if the plants were in bags that could be moved in the garage for the 1 - 2 days a years where it might matter. There is probably still over 5 months until first frost date.