Yes, OFFICIATE is a Scrabble word!

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

Is it a valid word?

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

act in an official capacity in a ceremony or religious ritual, such as a wedding
perform duties attached to a particular office or place or function