Sounds like he needs to learn a few basic commands, like OFF, LEAVE IT, etc. Have you had him to training classes yet?
I would not use the crate as a time out. Instead I would limit access to most rooms, using a baby gate, and leash him to you when you let him in the other parts of the house, for short intervals. Practice obedience commands, like DOWN, and SIT, while you are in there. And when he jumps, tell him EH! OFF, then give him a SIT or a DOWN command.
Let him play with toys while you are in there, and when he tries to chew on a table leg or couch, tell EH! MINE, then show him his bone or chew or toy and say YOURS, and give it to him. He will get it. GSDs are smart. But you have to supervise him every moment for a short while until he starts to figure things out. Then you can drop the leash for a little while longer. Leaving the leash drag will make it easier for you to catch him and correct if necessary. Once he has figured things out, he can spend his inside time off lead and longer times.
Some dogs are a lot easier than others. Sometimes we forget the pains of puppyhood too.
Jenna, RN CGC & Babs, CD RA CGC HIC
Heidi, RA CGC
SG3 Odessa, SchH1, Kkl1, AD
Ninja, RN CGC & Milla, RN CGC
Joy, Star Puppy, RN CGC
Dolly CGC & Bear CGC