You have entered the "teen GSD zone".
I think you're very lucky that you didn't have so many issues during the younger puppy hood. Looks like you're getting it in spades now, though. Hate to say it, but it's typical GSD behavior. They can be stinkers! I'd suggest a Veri kennel with the multiple locks. I had a male that started tearing apart expensive wire crates when he was older. I now use a kennel instead. My current pup loves his so he doesn't try to break out, but I think it would hold him if he did try.