I'll 2nd what Bob says...
The 7D Mark II is heavily optimized toward action photography (the 1D X Mark II is even more heavily optimized toward action photography but that's in a completely different price category). This is Canon's highest-end APS-C size sensor camera body.
The 80D is a slightly step below the 7D II. It's above the the whole Rebel line and specs and performance ... but not quite up to the level of the 7D II. It's doesn't quite have the continus burst speed of the 7D II, but it's beats all the Rebel bodes and it does such an impressive job of it that for many people it more than meets their needs. This is Canon's 2nd highest-end APS-C sensor camera body. The xxD series bodies (such as the 80D) are mid-range bodies.
Slightly below the 80D is the T7i. It's the top-end of the Rebel series. The T7i (and the 77D) offer some of the most significant improvements to the Rebel line than Canon has had in years. This camera isn't going to compete with a 7D II... but it'll be a huge performance leap over your XS.
The 77D is basically a super-Rebel. Canon announces a new Rebel series body just about every year. But last year they announced both the T6i and T6s at the same time. The sensor, focus system, ISO range, shutter speed... everything was identical between those two cameras. The big difference was that the T6s had an LCD panel on top of the camera, an extra dial on the rear, and a control layout more similar to their mid-range and pro bodies (not exactly the same, but closer than any other Rebel) whereas the T6i had a control layout more like the Rebels.
This time around Canon introduced the T7i as the latest model... and then the 77D. You can think of the 77D as being the "T7s" counterpart to the T7i. It has the identical sensor, performance, focus system, etc. as the T7i. But it has the extra control layout and rear dial similar to Canon's mid-range bodies (just like the T6s had). In many ways I wish they had just stuck with T7s istead of 77D as it isn't really a mid-range camera. One distinguishing feature that (nearly) all mid-range cameras have is auto-focus micro-adjustment (AFMA). This allows you to tweak the performance of the auto-focus system for each lens so that subtle amounts of back-focus or front-focus are corrected. The 77D doesn't have AFMA. It does have an internal interval timer (which none of the Rebel bodies have).
One more thing... you may wish to consider are some new lenses.
While outdoor daytime sports typically offer lots of light... indoor sports (such as basketball) typically have poorer light... poor enough that variable focal ratio zoom lenes (low cost entry level zoom lenses) often struggle to gather enough light to allow for a fast shutter speed (often not fast enough to freeze action). Zooms that can offer low focal ratio (such as f/2.8) at any focal length will let you collect considerably more light and that means you can shoot with faster shutter speeds. For example, the EF 70-200mm f/2.8L IS II would collect 4x more light than say... the EF-S 55-250mm f/3.5-5.6 because the 55-250 is going to be shoot at f/5.6 at the long focal length end (probably anything from around 150 or longer). f/2.8 collects four times more light than f/5.6. That means you can use a shutter speed which is four times faster (or you can shoot at a lower ISO setting for less noise.)
The downside to those low-focal-ratio zooms is that they aren't cheap. The 70-200 f/2.8L IS II is around $2k new.
Tim Campbell
5D III, 5D IV, 60Da
