Yes, CELLARS is a Scrabble word!

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

Is it a valid word?

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

the lowermost portion of a structure partly or wholly below ground level; often used for storage
an excavation where root vegetables are stored
storage space where wines are stored

Also: root cellar, wine cellar.