I know it sucks but at least they are just being kids as opposed to smelling weed in your apartment of having beer cans thrown off the balcony. As a mom of a 13 year old I will take this over some of the other dumb shit a lot of them are pulling.
I feel your pain. The people above us have 2. year old twins. Those kids run from the time they wake up (6:30 AM every single day) until the time they go to bed. They also have wheeled toys, stomp, jump, etc. It sounds like the damn ceiling is going to come down on me. It's not like I can ask them to not let their toddlers run around. It blows. I told my H we have to move because I can't deal with this for the next 15 years.
It's a tough age. Too old for aftercare at school, the moms at the playground would side eye them if they showed up there, so they're left to play upstairs afterschool.
I know it's annoying, but I'd take them over the twenty somthing with the garage band across the street.
I like the mix tape idea; maybe bake them some cookies, too. And then let them know how sound travels into your unit.