I would have tucked in next to that cabinet (other side of where father is crouching) if league rules allowed. If you can't shoot from behind the basket, try to get as close to the corner of the court. I have shot a lot of basketball from Pro to U6, and I can tell you from experience that profile shots (those from the side of the court) do not work well. Study a college or pro game on TV to see where the photog's are sitting, then compare the shots you see in SI or ESPN - for the most part they are straight on action shots. Save the sideline profile shots for break in action shots.
While I agree with shooting tight and in portrait mode, you can mix it up with horizontals under the basket scrums for the ball. Personally, I am not a fan of going any shallower than f4, but there are gyms where lighting conditions dictated f2.8. Fortunately, that gym looks to have consistent light. Just watch those windows which be a problem at certain times of the day. Try and keep your shutter speed high enough to meet the action - younger kids might mean 1/125-1/250 while older kids could be 1/250-1/500.