Yes, CULTURAL is a Scrabble word!

Letter values in Scrabble US: C 3, U 1, L 1, T 1, U 1, R 1, A 1, L 1.

Is it a valid word?

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

of or relating to the arts and manners that a group favors
denoting or deriving from or distinctive of the ways of living built up by a group of people
of or relating to the shared knowledge and values of a society
relating to the raising of plants or animals