As the others have said pretty much got 3 options:
I reckon it would be about £30 in a taxi.
Walking to the train station you'd probably have to leave by 9.40 to defo get there in time. The game is probably going to finish between 9.40-9.45 so you might have to leave just before the end. If you miss the train the wait is an hour to the next I think.
As J20 has said, if you get a cab from the ground to the station you'd make it easy, but its just a question of whether there is one - maybe best bet to walk to the Asda which is only 5 mins away and get a cab from there as there are usually a few cabs waiting outside.
If it was me (being a tight booty), I'd just walk it to the station and be on the way walking by 9.40.