Pups can generally hold their pee/poo at that age for 2 to 3 hours tops. You should get him on a schedule to go out every 2 hours, when he wakes up from a nap, gets done playing, 30 minutes after eating etc.. Both morning and night, so you will lose some sleep for a while. Rule of thumb is they can hold it 1 hour per month of age plus 1 hour, but that isn't always true as each pup is different. He should have just enough room in the crate to sit, lie down and turn around which looking at your pic is just about right. Getting him on a schedule will help alot, and if you have to leave him crated to go to work try to get someone to come by and let him out to keep the schedule as much as possible.