The afternoon buses go on the same routes as the morning buses (including to Bowie). They leave shortly after the school day ends, so the time varies slightly by day, and that is the only bus departure in the afternoon. If your child is participating in sports or other after school activities, evening transportation would be up to you to arrange.
As a side note: The current bus routes, morning schedules, and rates (including the route to Bowie) can be found on the Parents section of the website, which I have found to be a great source of information as an SJC parent.