Proper crate training can be a huge asset in raising a dog. If done right the dog learns that his crate is his safe place not a cage he needs to be locked into. You will also be better able to keep an eye on him. When he can't be watched 100% put him in his crate with a Kong or other toys to keep him occupied. When he is out of the crate get a short leash and fasten that to your belt. This way he can't get into trouble because you are right there to redirect him.

It's much easier to train a dog to not do wrong things than it is to try to extinguish behaviors that have already become habits. Tethering and crate training go well together and your dog won't develope the bad habits to begin with.