I never crate trained so cant help with that bit but a few people on here have said about they dont put a blanket in the crate with them because they would pee on it chew it etc and it helped.
Also as hes still very young maybe just lettin him out once a night isnt enough? He still has only a very small bladder i used to let Meeko out 3/4 times a night between 10pm and 6am at first then made the time frame a little longer until he eventually went all night. it was easy for me though as i had a young baby.
Also what about taking his water up and restricting it close to bed time? So when he empties his bladder before being crated it really is completely empty? Good luck xx