My impression of SF is that 9:30 is definitely at the tail end of the rush-hour. You can see that in the Caltrain schedules (express trains run ~6:30-9:00am), a

My impression of SF is that 9:30 is definitely at the tail end of the rush-hour. You can see that in the Caltrain schedules (express trains run ~6:30-9:00am), and even if you just walk around the city. There's a lot of activity already by 7am, while the bustle is noticeably starting to die down after 9am. There are some workplaces that don't start the day until ~10am (some tech companies, restaurants that don't do breakfast, maybe some stores), but the city seems pretty up-and-running long before that.