I just purchased the 80D about a month ago. I was using a 50D previously. I used center point on the 50D for my kids soccer.
With the 80D I actually went to a center grouping of 9 focus point and have been very happy with the results. (More Keepers, less missed focus shots)
I don't know for sure if you can select the center point in sport mode I usually shoot in AV TV or M. You can definitely select center point in those others
Use sport mode and take a photo, review that photo and use av, tv or M with the same settings.
I usually will shoot soccer with the following in AV (80D 70-200mm+1.4x teleconverter)
Iso 400, Aperture 4.0 ( the camera will vary shutter speed to properly expose) Try to keep shutter speed at least 1/500 bump iso up if you need more shutter speed
Good Luck and Happy Shooting