Yes, BUMPERS is a Scrabble word!

Letter values in Scrabble US: B 3, U 1, M 3, P 3, E 1, R 1, S 1.

Is it a valid word?

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

a glass filled to the brim (especially as a toast)
a mechanical device consisting of bars at either end of a vehicle to absorb shock and prevent serious damage