Yes, ACCEPTANCE is a Scrabble word!

Letter values in Scrabble US: A 1, C 3, C 3, E 1, P 3, T 1, A 1, N 1, C 3, E 1.

Is it a valid word?

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

the mental attitude that something is believable and should be accepted as true
the act of accepting with approval; favorable reception
the state of being acceptable and accepted
(contract law) words signifying consent to the terms of an offer (thereby creating a contract)
banking: a time draft drawn on and accepted by a bank
a disposition to tolerate or accept people or situations
the act of taking something that is offered

Also: banker's acceptance.