What works for different families will always be different.
That said, since you asked what "we" (other families) do, here's what I do:
My kids are 9th grade and 12th grade. This year, my senior son drives them both to school every day. No bus this year. They set their own alarms and get up on their own and get their showers, make their own breakfasts (if they are so inclined, sometimes they don't want to eat, or grab something for in the car or after they get to school before classes start).
Yes, I still get up. I set my own alarm (not quite as early as they set theirs). It has happened (once this year--our kids have been back for a month already) that one fell back asleep after his alarm went off (sister was in the shower and he laid down to wait for her to get out, and fell back asleep. She didn't notice he wasn't up when she got out of the shower, went in her room to dress/get ready, and had no idea he wasn't up also). So, I get up to be sure no one else oversleeps and that they are ready to go and get to school without son having to exceed the speed limit.
I also like to see them off, tell them to have a good day, that I love them, etc. As teens, they are not always receptive to this sort of thing. But, I don't care. I'm their mother, and it will be one of those constants that they will have as long as they live in our home. That stability is something that they will always carry with them.
It's also sort of an unspoken rule in our house that you tell people bye. I'm by no means a fatalist, or paranoid. But, if something should happen while they are away at school (or work, or with friends, or whatever), I want to have told them I love them that day. The day is coming (quite soon for our eldest) when he will live elsewhere. And I won't even SEE him every day. I am taking full advantage of telling him I love him every single day until then.
We are giving him his wings, and watching him learn to fly. But I tell him I love him before he flops out of the nest every morning, too. :)
Do what works for you and your family. If you need your sleep, then when they are able, let them go it on their own. If you can manage getting up to see them off, then do, if you enjoy it. You can still make their lunch the night before, if you are so inclined, and get up in the morning to say, "Have a great day, good luck on your test, I love you!"