Yes, ASCENSIONS is a Scrabble word!

Letter values in Scrabble US: A 1, S 1, C 3, E 1, N 1, S 1, I 1, O 1, N 1, S 1.

Is it a valid word?

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

(Christianity) celebration of the Ascension of Christ into heaven; observed on the 40th day after Easter
a movement upward
(New Testament) the rising of the body of Jesus into heaven on the 40th day after his Resurrection
(astronomy) the rising of a star above the horizon
the act of changing location in an upward direction

Also: ascension day, ascension of the lord, ascension of christ.