Yes, CABINET is a Scrabble word!

Letter values in Scrabble US: C 3, A 1, B 3, I 1, N 1, E 1, T 1.

Is it a valid word?

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

a piece of furniture resembling a cupboard with doors and shelves and drawers; for storage or display
persons appointed by a head of state to head executive departments of government and act as official advisers
a storage compartment for clothes and valuables; usually it has a lock
housing for electronic instruments, as radio or television

Also: storage locker.