Yes, WATCHES is a Scrabble word!

Letter values in Scrabble US: W 4, A 1, T 1, C 3, H 4, E 1, S 1.

Is it a valid word?

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

a small portable timepiece
a period of time (4 or 2 hours) during which some of a ship's crew are on duty
a purposeful surveillance to guard or observe
the period during which someone (especially a guard) is on duty
a person employed to keep watch for some anticipated event
the rite of staying awake for devotional purposes (especially on the eve of a religious festival)

look attentively
follow with the eyes or the mind
see or watch
observe with attention
be vigilant, be on the lookout or be careful
observe or determine by looking
find out, learn, or determine with certainty, usually by making an inquiry or other effort

Also: lookout man, watch over, keep an eye on, take in, look on, look out, watch out, find out.