A chain breaker tool is around $7 on Amazon. It's not hard to push out a pin from the chain to size it.

Since it's a new chain I'd put in a few links with another removable link, I've done it before. The shop probably has extra links of chain. I'm not even a pro and I've got nearly a drawer full of 8, 9, 10 and 11 speed links from different manufactures.