Yes, RYES is a Scrabble word!

Letter values in Scrabble US: R 1, Y 4, E 1, S 1.

Is it a valid word?

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

the seed of the cereal grass
hardy annual cereal grass widely cultivated in northern Europe where its grain is the chief ingredient of black bread and in North America for forage and soil improvement
whiskey distilled from rye or rye and malt

Also: secale cereale, rye whiskey, rye whisky.