Coaching Psychology

great question - but by in large, the old Parcell's quote rings true...
"If puppies don't bite when they're young, they're probably not going to bite when they get bigger"

Meaning....kids have their own "identity" if you will. Some kids respond to various stimuli more so than others. The thing is finding each "trigger" or "thumbscrew" for each kid. Football doesn't necessarily require various forms of psychological patterns - the "alpha" male mentality is the facet you want in every play, an air of confidence and determination to be the very best.
Some kids buckle under pressure - some claw and scratch to the top.... you can easily find that out in performance-focussed drills in camp. Some kids will have every aspect of your game plan down, plays, adjustments, etc...but have no heart or confidence to execute it....

That is the big "trick" to work as an enabling force to CULTIVATE the best results for each kid...some need nuturing, some need to be driven, some need fear, etc....

As far as "tests" - the only one I can think of is the old "Oklahoma" Drill" one-on-one.... the alpha males will make themselves known...and will show who you can trust when it hits the fan during the game...