Yes, IMPACTION is a Scrabble word!

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

Is it a valid word?

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

the condition of being pressed closely together and firmly fixed
a disorder in which feces are impacted in the lower colon
a disorder in which a tooth is so crowded in its socket that it cannot erupt normally
a sharp collision produced by striking or dashing against something

Also: impacted tooth.