YES! I race bikes, and I finished chemo in Jan and had bmx in Feb. I have returned to racing. Am I at 100%? No. But, I can push darn hard and am racing in the middle of the pack, which is pretty awesome.... Next year, baby... next year!!!!!
Anyway, I think a timeline of a couple or a few months before starting the academy is totally doable. The implant placement will be loads easier than the bmx plus explanders placement.
Did you have to have chemo?
Keep moving... Or get moving if you haven't started yet... And build your strength so that you go into the agility test able to do 50% more than what's required. You already know how to do that. It'll just take a little more patience... and no time like the present to get started. You can walk the day after your bmx.... just start slow... and then work your way up.