Yes, ATTIRING is a Scrabble word!

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

Is it a valid word?

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

Also: dress up, fig out, fig up, deck up, gussy up, fancy up, trick up, deck out, trick out, get up, rig out, tog up, tog out.