Yes, CONTRACTORS is a Scrabble word!

Letter values in Scrabble US: C 3, O 1, N 1, T 1, R 1, A 1, C 3, T 1, O 1, R 1, S 1.

Is it a valid word?

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

someone (a person or firm) who contracts to build things
the bridge player in contract bridge who wins the bidding and can declare which suit is to be trumps
(law) a party to a contract
a bodily organ that contracts

Also: contractile organ.