I would go to a dive bar personally, those are all over everett, malden, chelsea, melrose etc
If you go in boston chances are you're not gonna hear much of the game. Maybe the longhorn steakhouse? Its right around the corner from fenway, next to a movie theatre..probably not a huge game atmosphere in that place. I'm sure there would be plenty of people watchin, but it's a family place so it wouldnt get too rowdy I dont think