Yes, PROMOTION is a Scrabble word!

Letter values in Scrabble US: P 3, R 1, O 1, M 3, O 1, T 1, I 1, O 1, N 1.

Is it a valid word?

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

a message issued in behalf of some product or cause or idea or person or institution
act of raising in rank or position
encouragement of the progress or growth or acceptance of something
the advancement of some enterprise

Also: promotional material.