Yes, REFORMATION is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, F 4, O 1, R 1, M 3, A 1, T 1, I 1, O 1, N 1.

Is it a valid word?

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

improvement (or an intended improvement) in the existing form or condition of institutions or practices etc.; intended to make a striking change for the better in social or political or religious affairs
a religious movement of the 16th century that began as an attempt to reform the Roman Catholic Church and resulted in the creation of Protestant churches
rescuing from error and returning to a rightful course

Also: protestant reformation.