Yes, AQUALUNG is a Scrabble word!

Letter values in Scrabble US: A 1, Q 10, U 1, A 1, L 1, U 1, N 1, G 2.

Is it a valid word?

AQUALUNG is a valid word in the official Scrabble dictionary (US) and the UK Scrabble Dictionary, but not in Words with Friends (ENABLE).

a device (trade name Aqua-Lung) that lets divers breathe under water; scuba is an acronym for self-contained underwater breathing apparatus

Also: aqua-lung.