Yes, VOLUNTARIES is a Scrabble word!

Letter values in Scrabble US: V 4, O 1, L 1, U 1, N 1, T 1, A 1, R 1, I 1, E 1, S 1.

Is it a valid word?

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

(military) a person who freely enlists for service
composition (often improvised) for a solo instrument (especially solo organ) and not a regular part of a religious service or musical performance

Also: military volunteer.