It's irrelevent whether the runs would have scored on a single.With two outs the runners should be moving on contact, so two runs will score easily if the ball is not caught, so in my book it goes as two RBI single...
The ball got past F9, so it's clearly at least a double. The rule for game-ending hits actually limits the value of extra-base hits by how many bases the winning run advanced - it doesn't give them more than they deserve. The batter wouldn't get a double if they took second on a throw home.