I think he thinks he is the Alpha in their little kid pack! Just trying to be the boss and tell them what to do!
You will need to help your children understand how to deal with the behavior. It's a good thing to redirect. Have them give the pup a favorite toy to keep him busy biting something that won't be hurt by it, lol. If they are letting him out of the crate, they have to deal with all that pent up energy in a positive manner. If they can take the time to play with the puppy (after letting him potty of course), a good half hour of tug or fetch should appease him enough so that they can continue with their homework in relative peace. If he has a favorite chew toy, they can give that to him after playtime, and hopefully he can amuse himself. Wosie's favorite chew right now is her mini-kong with a half slice of fat free american cheese stuffed in it. She will work on that for almost an hour!
Good luck!