How long is your drive home? Can they have a large snack/small dinner in the car on the way home? That would save you some time. Once they get home, stick them in a warm bath, then have them read or perhaps watch tv for a bit, if they like tea then maybe a cup of herbal tea. No playing, no fooling around, nothing exciting. Make it almost a ritual. If they're too excitable, no tv (all kids are different, mine find tv soothing, some get riled up by it). You know your kids best. Is there any way the boys can already be in bed by the time the girls get home? It would mean them seeing their sisters less, but i can imagine that they get each-other wound up... And that's not helping anyone get settled in and in sleep mode.
Dd is the same exact age and she usually gets home around 7:30, at which time we eat dinner, watch tv, read and have a snack (take a bath on some days). Her bedtime is supposed to be 8:30, she usually drags it out until about 9. On Mondays however, she gets home at 8:30 and it's a struggle to get her to eat and settle down in a reasonable time. I don't take her home on Mondays, a teammates parent does, so I can't feed her on the way. I need to start implementing some of these things to our own monday evenings!
Most of the time, the hour-hour and a half she has after gym (except on Mondays) is sufficient for her to settle down and go to sleep. She does need some down time and a chance to see her dad now and then, lol! We do have to kinda be hard about bedtime and enforcing settle down time though, because she definitely needs her sleep. She's allowed to do some reading once she's in bed, she doesn't "abuse" that (as if any reading could be bad, really....) unlike my 12 yo who will gladly read until midnight when she's caught up in a book and then be miserable the next day.
I think her bedtime "ritual" helps her, it helps put her mind to the fact that it's bedtime.
Good luck, it's really hard to combine serious training with reasonable bedtime for these young kids!