Yes, SEQUENCER is a Scrabble word!

Letter values in Scrabble US: S 1, E 1, Q 10, U 1, E 1, N 1, C 3, E 1, R 1.

Is it a valid word?

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

(chemistry) an apparatus that can determine the sequence of monomers in a polymer
computer hardware that sorts data or programs into a predetermined sequence

Not playable in Scrabble US: SEQUENATOR.