Yes, EXTRAORDINARY is a Scrabble word!

Letter values in Scrabble US: E 1, X 8, T 1, R 1, A 1, O 1, R 1, D 2, I 1, N 1, A 1, R 1, Y 4.

Is it a valid word?

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

beyond what is ordinary or usual; highly unusual or exceptional or remarkable
far more than usual or expected
(of an official) serving an unusual or special function in addition to those of the regular officials

Also: over-the-top.