The "stuff in the background" is going to be minimized by using the lens at f/2.8 or 3.5 and racked out to the full 200mm setting. Even then, it may not throw the junk out of focus enough for your liking. If you have Photoshop or Photoshop Elements (or another similar editing program), you can apply a blur to the background and minimize the appearance. I'm sorry I didn't have time to put into this (I have two acres of leaves to get up before it snows), but here's 10 minutes worth of cropping and gaussian blur.

Thanks... I scanned the thread but missed what lens was being used.

I'm viewing the images on a desktop with a calibrated graphics quality monitor and focus appears accurate, lens looks to be sharp, color and exposure are good. (First image shot in shade is a little cool, but that's easy to fix in post processing).

The problems I see...

70-200mm is often just not long enough focal length for a soccer field, even on a crop camera (would be even worse on a full frame 6DII).

I use 70-200mm for sports myself. In fact it's probably my most-used lens... enough so that I have two of them. At most sporting events, one of them is on one of my cameras.

HOWEVER, my other camera has either a 300mm f/4 or a 100-400mm on it, at events with a large field like soccer. The longer focal lengths are often necessary.

I think much of the problem with the original poster's images are related to that... A longer focal length that makes for a tighter shot would be better, putting more emphasis on the active subject and reducing the background. Related to that, the composition can be improved. Without a longer telephoto lens to use, either limiting to shooting when the action is closer (where I use my 70-200s) OR cropping the image in post-processing would help make for better shots. There's loss of resolution when images are cropped. But working with a 24MP camera like T6i and so long as there aren't big prints being made from the images, some cropping can be done without too much loss.

I also try to keep an eye on the background.... when possible, positioning myself where it might be more favorable. Of course, this doesn't always work out, you gotta shoot the action where it happens, not where you want it to happen! That's where Photoshop comes in and I might "remove" a distracting person or object from the background. Using longer lenses also will increase background blur and can help. I prefer to shoot RAW, too... which have a lot more latitude for editing and adjustments in post-processing, when needed. But at the very least, shoot the largest and highest quality JPEGs (but your camera settings need to be correct... since the images will be "processed in camera" according to them).

Finally, for sports I often use vertical/portrait orientation. For one, it's more "active" than horizontal/landscape orientation. But it also often allows tighter shots.

For example, here's what I'd do with one of your images. Note: I quickly and crudely Photoshopped out two people in the background, but cannot do a very good job of it working from a low resolution JPEG... Mostly I just cropped and straightened, and changed to vertical orientation... I also boosted color saturation a little (your camera settings control that, if you are shooting JPEGs).

Again...

What do YOU think is wrong with those images?

They look like fairly typical sports shots to me. Good color and, as near as I can tell at those sizes, accurate focus.

Precisely what lens(es) are you using?

Auto focus performance is an important factor shooting sports. Both lens and camera (and user, for that matter) have a big influence on that. T6i has 19-point AF system that is largely the same as was used in 70D, which in turn inherited a somewhat dumbed down version of the very high performance AF system that the original 7D used. Combine that with high performance USM lenses for auto focus that's fast to acquire focus and good at tracking movement. In addition, the focus techniques that you use are very important.

With more info we may be able to give you more help.