Yes, ACQUIRER is a Scrabble word!

Letter values in Scrabble US: A 1, C 3, Q 10, U 1, I 1, R 1, E 1, R 1.

Is it a valid word?

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

a person who acquires something (usually permanently)
a corporation gaining financial control over another corporation or financial institution through a payment in cash or an exchange of stock
the financial institution that dispenses cash in automated teller machines and collects a fee from the bank that issued the credit card
a credit card processing bank; merchants receive credit for credit card receipts less a processing fee

Also: merchant bank.