Is he getting up because he has to go out, or does he just want out of his kennel? Does he sleep in the room with you?
At this age, he can make it through the night without going out (as he's already proved) so you might have to try some tough love. At the moment, he's training you! You have to reverse the process. I'd cover his kennel with a light blanket or sheet if he's in a wire crate and withhold water before bed and for the overnight until he gets through this.
First, be sure there isn't a medical reason. If he isn't going to the bathroom more during the day too, it's probably not a urinary infection. If he is, check with your vet to see if something is going on.
Now the tough part. If he's in the room with you, you'll have to just say "quiet!" firmly and not get up. He will cry, and yip, but he'll stop eventually and after a night or two or three -- depending on how stubborn he is -- the cycle will be broken and your sleepy puppy will be back. If he isn't in the room with you, you'll have to just ignore him for a few nights until it stops. Also make sure he gets lots of exercise and play time before bed so he's tired.
Good luck! Let us know how it goes.