Yes, BRAKES is a Scrabble word!

Letter values in Scrabble US: B 3, R 1, A 1, K 5, E 1, S 1.

Is it a valid word?

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

a braking device consisting of a combination of interacting parts that work to slow a motor vehicle
a restraint used to slow or stop a vehicle
any of various ferns of the genus Pteris having pinnately compound leaves and including several popular houseplants
large coarse fern often several feet high; essentially weed ferns; cosmopolitan
an area thickly overgrown usually with one kind of plant
anything that slows or hinders a process

Also: brake system, pasture brake, pteridium aquilinum.