I'm currently doing my alevels. I didn't have a job at all during sixth form, I'm starting my first job this summer. A lot of my friends did have jobs, but for me I felt like I wouldn't have enough time to study on weekends. My friends who did have part time jobs on the weekend, just did more work during the week and that worked for them. Just do whatever works best for you.
Re driving, I started learning in the summer last year, and then did my test in the middle of April this year. I had a lesson once a week but quite a few were cancelled, which is why it took quite a long time. For me this felt like good timing. I'd advise not doing your test any later then the middle of April, otherwise it takes too much focus away from exams, and if you don't pass it still gives time to book another test (or 2) in the summer. I would advise learning to drive during sixth form, unless you are taking a gap year, just so that you have the option to drive around during the holidays when back home and because it's really difficult to learn in just the holidays as consistency is so important.
Would add that even though you're learning to drive or passed, it doesn't mean you need a car. If your parents or siblings have one, just learn in that, as it's expensive to have your car sat at home whilst you're at university, or to take it to university it's a bit of a faff