How much exercise is he getting daily? not just a stroll around the block but actual exercise suitable for a energetic, young GSD?
Is he crated during the day when everyone is gone?
Up his daily exercise and training time, I noticed you said "running time" do you take him out running for long periods of time?
At 8 months old he shouldn't be running constantly or long periods of time, especially on hard surfaces. Make sure he is getting mental exercise, you can run him all you want but nothing is going to be as good as tiring him out both mentally and physically. Give him plenty of suitable chew toys, of different flavours, brands etc.. If you can't provide this, look into getting a dog walker to come and help get some extra energy out during the day while everyone is gone. (not as his only exercise he gets though)
I dont know what to tell you other than crate him during the night, it is an option, the only thing stopping it from being an option is you not being able to handle it. He will catch on that he goes in the crate at night after his last trip outside, that it is time to sleep and be quite. Just completely ignore him and have suitable safe chew toys for him in the crate. If he is getting the proper exercise and training, he will be mentally and physically fulfilled enough to be able to settle down and sleep. He is a puppy, of an energetic breed who requires lots of exercise and attention to be healthy and happy mentally and physically. It is great that he is getting lots of love from you and your family, but exercise and training is just as important, if not more important for a young crazy puppy.
hes a pup, if he isn't given the right stimulation and exercise he will be bored and energetic, he will look for something to do, chewing the carpets and the rest of your house is something to do. Pups are like young kids that always need to be watched or given something fun to do, or else they take it upon themselves to find something fun to do, usually that is ruining the house. If he isn't being watched and isn't fulfilled he MUST be crated, it is dangerous to leave a known chewer out of the crate at night, could very easily eat something else and end up with foreign body. A major vet bill and surgery is much more stressful and expensive than putting up with a few nights of no sleep and listening to crying and barking, or replacing a carpet.
Not trying to judge you or anything so please dont take anything that way, but you seem to be a very busy family, what brought you to the decision to bring a puppy into the family?