Yes, SMOOTHERS is a Scrabble word!

Letter values in Scrabble US: S 1, M 3, O 1, O 1, T 1, H 4, E 1, R 1, S 1.

Is it a valid word?

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

a power tool used for sanding wood; an endless loop of sandpaper is moved at high speed by an electric motor

Also: drum sander, electric sander.