Yes, EMPORIUM is a Scrabble word!

Letter values in Scrabble US: E 1, M 3, P 3, O 1, R 1, I 1, U 1, M 3.

Is it a valid word?

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

a large retail store organized into departments offering a variety of merchandise; commonly part of a retail chain

Also: department store.