Yes, LACROSSE is a Scrabble word!

Letter values in Scrabble US: L 1, A 1, C 3, R 1, O 1, S 1, S 1, E 1.

Is it a valid word?

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

a game invented by American Indians; now played by two teams who use long-handled rackets to catch and carry and throw the ball toward the opponents' goal