If you are only shooting to share on the web, then you can get away with less of a zoom (thus aiding stability & thus sharper photos) & then just crop to the action point. I managed to get some decent shots once (now lost ) from a rugby match with only the kit 18-55mm lens I had on the 300D at the time...albeit when they were closer to my touchline
For your shots I think a couple with tighter crops would work better (IMHO). eg:-
If you look at any football photo's in the papers then it's usually only 1 or 2 people in the shot & very tight crop (but then again they have huge lenses ). Wider shots work when you can see a reaction in the crowd....if there is one
You could also look to place yourself at the end of the pitch, as that's the way the opposition will be facing , so you can get the face shots others talked about....plus hopefully you'll capture that overhead scissor kick that scores the ultimate goal
Good shots by the way for 1st time