Yes, UNIQUER is a Scrabble word!

Letter values in Scrabble US: U 1, N 1, I 1, Q 10, U 1, E 1, R 1.

Is it a valid word?

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

radically distinctive and without equal
(followed by `to') applying exclusively to a given category or condition or locality
the single one of its kind
highly unusual or rare but not the single instance