Am I right in thinking you have a very large GSD/Wolf cross?
If you have then nothing will contain him in the house and Kongs will not hold his attention for long (if they last long!) Have you thought of a putting a water pool in the yard for him to cool off in? A plastic pool will probably not last long but a stone or cement trough large enough for him to lay in might work.

If you do have a wolf cross that is showing this dominant behaviour towards you (growling when he's been crated and when you touch other dogs) I would seriously urge you to get some experienced help to get this under control. The more he grows and matures emotionally the more sure he will be of himself and the more difficult it will be to control. I'm not saying all wolf crosses are bad BUT they do need special handling and understanding.