Yes, REVELATIONS is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, V 4, E 1, L 1, A 1, T 1, I 1, O 1, N 1, S 1.

Is it a valid word?

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

the speech act of making something evident
an enlightening or astonishing disclosure
communication of knowledge to man by a divine or supernatural agency
the last book of the New Testament; contains visionary descriptions of heaven and of conflicts between good and evil and of the end of the world; attributed to Saint John the Apostle

Also: divine revelation, revelation of saint john the divine, book of revelation.