Yes, POACHER is a Scrabble word!

Letter values in Scrabble US: P 3, O 1, A 1, C 3, H 4, E 1, R 1.

Is it a valid word?

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

someone who hunts or fishes illegally on the property of another
a cooking vessel designed to poach food (such as fish or eggs)
small slender fish (to 8 inches) with body covered by bony plates; chiefly of deeper northern Pacific waters

Also: sea poacher, sea poker.