Thanks for sharing!
Is it common in Greek tradition for blessed to act as subdeacons (I doubt that kids are ordained subdeacons) to cense?
The Greek tradition doesn't have the same hangup about who can cense like the Russian tradition has. The fact that the kids are using the hand censer to cense the church makes sense in that the hand censer is very common even in Greek household to cense the home. In some monastic practices the hand censar belongs to the ecllesiarch and he does the censing at the start of Orthros and before the meals even if he is not ordained.
I don't think I've ever seen a kid cense the church (kazion or not), but I have seen them cense the icon carried by the priest, or the gifts in the Great Entrance; and certainly they've held the censor between uses (for Artoclasia, Memorial/Trisagion, etc.).
"O Cross of Christ, all-holy, thrice-blessed, and life-giving, instrument of the mystical rites of Zion, the holy Altar for the service of our Great Archpriest, the blessing - the weapon - the strength of priests, our pride, our consolation, the light in our hearts, our mind, and our steps"
Met. Meletios of Nikopolis & Preveza, from his ordination.