Yes, BRACKETS is a Scrabble word!

Letter values in Scrabble US: B 3, R 1, A 1, C 3, K 5, E 1, T 1, S 1.

Is it a valid word?

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

a category falling within certain defined limits
either of two punctuation marks (`<' or `>') used in computer programming and sometimes used to enclose textual material
either of two punctuation marks ([ or ]) used to enclose textual material
a support projecting from a wall (as to hold a shelf)

Also: angle bracket, square bracket, wall bracket, bracket out.