Beginner zone 9

Hi, I'm somewhat new to gardening. I'm in Central California zone 9. I'm a bit confused about fall crops. What veggies can I plant *if anything* during the end of Sept starting from seed in my zone? I'm hoping to do one 4x4 raised bed to start out but, I'm not clear on whether I'm too late or not as I'm reading what seems to be unclear or conflicting info on my state. Thank you !

In zone 9 you should have a month to 2 months when frost is possible. That doesn't mean you'll get any (this depends on your environment and location as well as a lot of other variables) but it's possible. That would be beginning of December to end of January. You could also get a solid freeze, but that's less likely.

Most plants require between 60 and 100 days of frost free weather to fruit. Starting beginning of October, that's 60 days to your first (average) possible frost. So there is still time for some things. If you have a greenhouse or can put up cold frames (I use one layer of plastic over hot-cold PVC) you may well be able to grow through your short "winter" and give the plants a headstart for spring.

Remember that some plants will slow down considerably as the sun wanes, so the length of time to fruit may double. This is more of a problem in more northern locations. Consider what you know of your area and determine what you'll need. My suggestions would be garlic and onions in ground, lettuce and other greens in your box. Stick a few other short season items in there to test them and see how they do. Possibly a summer squash or zucchini. Also consider plants that will easily overwinter like beets or brassicas. They love cooler weather but they're more prone to insect attack.

Study the situation and learn, that's the most important thing at this point.

Cabbage, brocolli, or cauliflower would work. Only problem is you may only fit 2 plants total in that box.

I think you may still be in range for carrots, squash, or zuchini by seed. Lots of carrots, but zuchini and squash may be 2 plants total. 2 plants gives a great harvest though. More than we normally would eat.

Lettuce would give you ample salads in that size box until frost.

I would look regionally for a planting calendar. If i google "central texas planting guide" a good one comes up. Maybe do the same for your region.

There are almost certainly full planting guides and even books about winter vegetable gardening in Central California, that will give guidelines on what can be planted when. My California geography is very rusty but I found this one for Santa Clara County, which Google says is in Central California zone 9-10: http://mgsantaclara.ucanr.edu/garden-help/vegetables/vegetable-planting-chart/ Based on that it seems like there is quite a lot that can be planted right now!

If you`re a video kind of person, there is a youtuber called CaliKim29 who has a channel describing her garden in zone 9 in CA. She`s recently been posting videos about putting in her fall/winter garden. (https://www.youtube.com/channel/UCARXOI1UlItgIevoI5jZViQ )
I am zone 9 but zone 9 in California is nothing like zone 9 here in Bananaland, but sometimes I get some good ideas from her about things I can plant together.

I live in Northern California zone 9b so probably very similar.  Now is the time  to grow lettuces, broccoli, spinach, onions, carrots, peas. cabbage, October you can grow garlic.  If it's too hot to grow it in summer, you can grow it in fall/winter.  One year I planted peas, a little to late, they grew about knee high and stopped there.  Come spring they finished growing and we had a super crop of peas.  It is a wonderful place to live because you can garden all year round.  There is tons of info on the internet.  I signed up for the old farmers almanac garden planner.  You put in your zip code and they email you reminders about what you can plant that month.  I enjoy it a lot. There are also lots of people on Youtube who do ca. garden videos.  The cool thing about a lot of the winter things you can grow is most of them do well in pot, planters, even 5 gallon buckets with holes in the bottom, so you can try several different things without much cost.  I like to research and watch videos, and learn what I can, but the best  way to learn is just do it.  My summer garden did terrible this year, but I learned a lot, and there is always next year.  Have fun.