Yes, RELEASED is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, L 1, E 1, A 1, S 1, E 1, D 2.

Is it a valid word?

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

release, as from one's grip
grant freedom to; free from confinement
let (something) fall or spill from a container
prepare and issue for public distribution or sale
eliminate (a substance)
generate and separate from cells or bodily fluids
make (information) available for publication
part with a possession or right
release (gas or energy) as a result of a chemical reaction or physical decomposition
make (assets) available

Also: let go of, let go, bring out, put out, give up.