Cats are clingy in the morning because they've played all night and are hungry, so they stick to their owners for food and may even whine and beg. Usually, once the owner feeds them, they become less clingy.
Cats want to play with you. When cats get bored, they naturally think of their human and come over to lick you awake to pass the time and have a close interaction with you! Waking you up by licking you is a sign of a happy cat owner. Some cats, on the other hand, will use the rough method of slapping you awake. 
Cats are usually very active at night, and when it's time to rest in the morning, they like to go to sleep next to their owners, where they feel very safe.
