My Georgie does that too.

He usually sleeps curled around my head with his head on my cheek.

When he tries to wake me, he has a catologue of ideas starting with patting & poking my face and nose and ending with him bitting my head or my hair.

I think it is an attention seeking thing, maybe they are trying to groom us and get caught up with our hair. Or it could be a 'Wake up NOW Meowmy' thing.

He always looks so proud of himself when I finally open my eyes, I can't help but give him a cuddle, however early it is