It's doable, but it requires a hell of a customization...
I suggest this approach, then the others can contribute:
1) You have all the content of the squares inside an object "Rate" where you have your title, short description, long description, bla bla bla. The object will be shown by its title
2) You connect to the employee that object 3 times (one per each evaluator)
3) You make the field as a radio button
4) You put some CSS to make the 9 radios to show as a 3x3 clickable squares matrix
5) You put somewhere else in the same scene a table / list with all the 9 objects and then you hide it
5+6 BIS) You can do the same through API calls but why doing API calls when you get most of the information you need through views through the Knack.models[view.key].data ?
Additional tip: If you use the Knack.models either you're calling those inside a scene render or you have to add a check that ensures that the target view has rendered already otherwise your Knack.models[view.key].data will be undefined...