i dont let him in because he will pee and crap inside.
And he always will unless you're willing to train him. It sounds to me like you're not willing to do that. Dogs are pack animals, and even though we are human, we
are their pack leader. He is only a baby and needs a dominate leader. That is YOU!
You can leave the dog in the house and confine him to a specific area of the house with some hard chew toys, water, and something to lay on. Puppies will usually consume all the food you put down, so if fed properly before you leave the house, and provided you're not gone for long periods of time, he doesn't necessarily need food, but water is essential.
Dogs
generally will not pee or poo where they sleep so keep the space small, but do allow room to move around. Leave a radio on for comforting sound too when left alone. As young as this pup is, he will need to be taken out quite often, but as he gets older, the time between each outing can be decreased. Praise him with a doggie treat each time he does his business outside too. This will reinforce the idea.. Positive reinforcement works!
DO NOT punish him when he goes in the house! This is non productive as dogs live in the moment, and will not understand the punishment hours later.
As for the biting:
Using just the tips of your fingers, a firm
tap to the front of the dogs chest accompanied with a firm "no" should stop the biting, but you have to be consistant until he gets it. Have a toy ready so that you can immediately replace your hands with the toy. Same goes for anything else he's not supposed to chew. Always replace with something the dog IS allowed to chew.