Yes, VISIBILITY is a Scrabble word!

Letter values in Scrabble US: V 4, I 1, S 1, I 1, B 3, I 1, L 1, I 1, T 1, Y 4.

Is it a valid word?

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

quality or fact or degree of being visible; perceptible by the eye or obvious to the eye
degree of exposure to public notice
capability of providing a clear unobstructed view