Easy, just say no! There is no way he'll be able to keep that pace up for long before he burns himself out. He's only in Junior High! At that pace, by the time he gets to High School he'll probably be ready to throw in the towel.
Now is a good time to teach him how to pace himself and manage expectations. Tell him the work load will be significantly different next year and in the years to come academically. And academics should come first...not extra-curriculars.
Tell him one sport per semester (if that's how the year is divided--otherwise you get the idea). If soccer is his true love, then that's the activity he sticks with. But in all honesty, I don't see that going very far considering there may eventually be a conflict of interest where scheduling is concerned. He might find his own coaches frowning on the two sports in the same season... I mean what about practice times and all of that? Anyhoo, if for some reason there is no conflict, I agree, two sports and school is too much! Make him pick one.
Depending on how much of a time commitment student council is, that might have to take the back-burner too. Once again, will this conflict with football/soccer practice? In junior high, SC is probably a very minimal commitment compared to sporting activities where practices can consume the week and weekends. I say if SC is more than an hour or two meeting time every two weeks, forget it.
With all that he wants to do, something is going to suffer. Tell him it's better to be really good one thing instead of a Jack of All Trades. It can afterall be really stressful if you're aiming for perfection and excellence, but because you're spread too thin, all of your accomplishments are mediocre. What fun or how fulfilling is that. Is he thinking about how he'll feel if he disappoints team mates, or fellow council members if he starts skipping practices or meetings because he has too much going on? How does he feel about kissing his quiet time goodbye? Even teens need a quiet weekend or weeknight every now and then.