Yes, CUSPID is a Scrabble word!

Letter values in Scrabble US: C 3, U 1, S 1, P 3, I 1, D 2.

Is it a valid word?

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

one of the four pointed conical teeth (two in each jaw) located between the incisors and the premolars

Also: canine tooth, eye tooth.