My 90D settings
I have slightly different settings saved on the mode dial for C1 & C2 as follows.. (ie C1 mammals, C2 Birds in flight)
AI Servo!!
Focus points -
(these are my preference, not everyone will like the way these work, you'll need to use the joy stick to toggle around)
I use single point for the Hare or a bird in tree.
9 spot square for the birds in flight.
Large area will work, but can struggle with busy BG's, but setting a start point will help, see menu setting 11 below.
Menu button - C. Fn Menu settings (5th tab, Orange) - C. Fn II : Autofocus...
1 - Tracking sensitivity, I use +1 or 2 depending of the animal I'm after, the more agile the higher I go.
2 - Acceleration/deceleration tracking, I have this set as default for most, as if it is set too high it can cause erratic hunting. sometimes +1 for something coming in fast but may stop too (Hare or Dog etc..)
3 - AF point switching, +1, this speed up the reaction across the area.
4 - AI Servo 1st image priority, I keep as default, I did try to go to focus but found it held back too much.
5 - AI Servo 2st image priority, I use focus priority (+1) this can slow the frame rate but increases the chance of the next shot being in focus.
6 - Lens drive when AF impossible, I leave this as continue.
7 - Select AF mode - Default -
personal choice
8 - Limit AF methods - Default -
personal choice
9 - AF area selection - Default -
personal choice
11- Initial Servo AF point, this personal choice, but I use mode 2 AF set point, as this allows me to pick the large area AF start point. (I don't use this much, as I prefer small zones)
12 - Auto AF point selection : EOS iTR AF, I have this disabled ( mode 2) , I find it lowers the delay slightly as it's not 'looking' for faces, if you shoot people this may be better left on.
13- Personal settings, I've left as default.
14 - Personal settings, I've left as default.
15 - Personal settings, I've left as default.
16 - AF micro adjustment, handy thing to use if you need to adjust your lens to the body.
Canon Manual PDF posted below in case you don't have it. Menu section starts at page 552.
Hope this helps