I also
surf NorCal waves - Ocean Beach - although I wouldn't say that I have it dialed in the least. NorCal is very exposed and picks up lots of swell from all directions. If it's beach break you're surfing (like OB or Pacifica) then that also means that the sand bars are shifting and therefore the peaks are shifting to a large degree as well. Within a single hour, tides and swell can change enough that waves go from peaky, hollow tubes to big sloping closeouts. In short, that means that you can paddle out with a board that's perfect (for you) in those conditions only to have the conditions change and you find yourself wishing you were on a different ride.
In fact, it's notoriously tough. When the WSL tour came through SF, pros were complaining that the peak always seemed to be 30-50yds in the wrong direction (north, south, inside, outside). Plus, Dusty Payne exited his heat against Jordy Smith because he saw a great white.
If you've only just started surfing in July, then you can expect to get your ass handed to you on a regular basis regardless what board you're on, especially since we've been getting so much swell lately. Ultimately, you should prioritize what you want out of a session: making it through the whitewater? getting comfortable and finding position in big surf? catching big waves? As dtc says, these are competing priorities when you're still a beginner.
Even guys with experience will get rejected on overhead NorCal beachbreak. Learn how to read the break, look for the channels, time your paddle, ask an exiting surfer which way the current is flowing, then ask the Sea for mercy, and that 9'6" will get you out to the lineup faster than a shortboard will. Once you're out, work on getting comfortable in good position and that longboard will also help you get over any outside, cleanup sets that swing through (they will). When you've got that dialed, try shoulder hopping or knifing your drops and you'll find that 9'6" will get you in early (if you're paddling hard enough) and will be far more stable than a shortboard in the same conditions. If you've got all of that covered, then you can probably drop 2ft off your 9'6" and progress from there, BUT you still won't be able to duck dive a 7'6" with any great success.
All that to say, "Don't get discouraged, just get better!" Good luck!