Yes, NINEPINS is a Scrabble word!

Letter values in Scrabble US: N 1, I 1, N 1, E 1, P 3, I 1, N 1, S 1.

Is it a valid word?

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

a bowling game that is played by rolling a bowling ball down a bowling alley at a target of nine wooden pins
a bowling pin of the type used in playing ninepins or (in England) skittles

Also: skittle pin.