A friend of mine asked me how to keep her cat from waking her up at night. Having just finished getting my cat to stop I know what she is going through. So I offer the following advice.
Please be aware if this is a new behavior you may want to take your furry friend to the vet to make sure there isn't something wrong.
First thing you want to do is keep him busy during the day. Play with him throughout the day, give him windows to look out of, pet him, leave out toys, give him a good brushing and if he is willing you can try hooking him up to a harness and take him for a walk. (for some cats this takes some getting use to.)
Make sure he has food available all day. Unlike dogs, cats eat little meals all day long so make sure he has food available so he is not waking up due to hunger. Along with this make sure you don't feed him right after you wake up. You will be sending the message that wake up time is feeding time and he will wake you to feed him.
Don't give in. This one is hard and may take some time but you have to pull those covers over your head and completely ignore him during the time you want to sleep. Even yelling at him is giving him the attention he is looking for. Eventually he will get the message! It also helps to make the room as dark as possible as they don't see well in complete darkness. That means get those bright led electronics out of the room and some nice dark curtains on the windows. Though once again if its a new behavior go ahead and check it out he may be ill.
Last if all else fails Close the Door. If you cat just isn't getting the message then its' time to set him up a sleeping space somewhere else and shut him out. You may have to work at this one too since having him yowl outside the door won't help you sleep either. Try placing something in front of the door like a prickly mat or double sided tape on the door if he is scratching (trust me they hate getting sticky stuff on their paws).
It will take some time to retrain your best friend but it will be worth the effort.