I'll accept the mission.
Look at the two pic above.
The south door was where Kyron was last seen (either in or out)
If you notice there is a "dirt" road that comes in from the front road and runs along the soccer field. (Probably to bring equipment in and out). On the front road side - this "path" creates a "pull off" if you will from the main road.
I would have made sure "something" was left behind by the child in the vehicle. Then as I was preparing to leave and have him go to class, I would convienently ask the child, "do you have your________". Immediately the child would remember that he forgot it in the truck.
Ok, I tell him. You go to class and then come down those stairs to that door. I'll go get the truck and meet you out there - you can run out to the truck and get "it".
Again, look at those pics. There is tree cover that would conceal your vehicle from the second story windows and also trees that would provide some cover for the child as he "runs out to the truck". Cars on the road of course would see you - but if you are rummaging around or hanging out the window waving a schoolbook or papers while you're idling.......
Once the child is at the truck you tell him get in.
Of course you are risking being seen - but I believe this would minimalize those chances and if you are - well the child is just running out to get something. The exit to the school parking lot is behind you and you are not in the mainstream of traffic lanes (you've pulled off to the side). The parking lot exit goes both left and right, so at least some of the traffic will turn left and not even notice you.