Yes, RANGING is a Scrabble word!

Letter values in Scrabble US: R 1, A 1, N 1, G 2, I 1, N 1, G 2.

Is it a valid word?

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

change or be different within limits
move about aimlessly or without any destination, often in search of food or employment
have a range; be capable of projecting over a certain distance, as of a gun
range or extend over; occupy a certain area
lay out orderly or logically in a line or as if in a line
feed as in a meadow or pasture
let eat
assign a rank or rating to

Also: lay out, set out.