Yes, ALVEOLUS is a Scrabble word!

Letter values in Scrabble US: A 1, L 1, V 4, E 1, O 1, L 1, U 1, S 1.

Is it a valid word?

ALVEOLUS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a tiny sac for holding air in the lungs; formed by the terminal dilation of tiny air passageways
a bony socket in the alveolar ridge that holds a tooth

Also: air sac, air cell, tooth socket.