You also don't want Legal because it's not very good.

Some of the best seafood is being served up at Island Creek Oyster Bar, which happens to be very close to Fenway. Opentable shows that they have a table for 8 available at 9:30. Perhaps if you call you can get an earlier reservation.

East Coast Grill, in Cambridge but a fairly easy drive from Fenway, has a very seafood-centric menu, and takes reservations for parties of six or more. They also have excellent barbecue. Parking is tough in the area, but they have their own lot across the street ($5/car).