Really, other than not sharing info, LE has not handled this so abnormally, if they have no real info to share. They are not saying why they are searching where they are, but by the school is an obvious place to search if they don't know what happened, and the other place is probably from a tip or a cell phone ping of someone they might be looking at. None of this points to LE having any specific scenario in mind and asking for video just adds to the mix, let's look at everything, scenario. Also we have not seen a missing child coupled with a school in recent history, so maybe this is the way they would deal with any such case involving a school.
A person would still need time enough to talk Kyron into going with him/her, as they could not risk a struggle or a screaming, shouting child in the midst of this busy school where people know one another. That pretty much rules out a stranger to me.