My daughter finishes at 7:45pm, three nights a week. We have her dinner ready for her (in an insulated food container) to eat in the car on the way home. It saves time, and gets fuel into her again straight away. One less thing to be done when she gets home. Other girls from her squad finish training, then take their dinners brought from home and reheat them in the gym's microwave to eat immediately.
My daughter does all her homework on the days that she does not have training. Fortunately her homework is issued for a week, so she can do it on the days she likes. If she had some issued each day, to be handed in the next day, we'd probably have to see if we could come to some arrangement with her teacher. And given that each year we request a teacher who is supportive of her sporting activities, I would hope this wouldn't be a problem.
She doesn't do any homework in the car. Car journeys are refuelling times for her - she has a really fast metabolism, so has to eat regularly. On the way to gym she eats a second lunch and gets changed. There wouldn't be time to do homework as well!
I guess we all do things a little differently. You just have to be a bit creative with using the time available wisely!