Yes, SUNGLASSES is a Scrabble word!

Letter values in Scrabble US: S 1, U 1, N 1, G 2, L 1, A 1, S 1, S 1, E 1, S 1.

Is it a valid word?

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

spectacles that are darkened or polarized to protect the eyes from the glare of the sun
a convex lens that focuses the rays of the sun; used to start a fire

Also: dark glasses.