Depending on how big your kid is, a backpack might be unmanageable for him.
I had my two kids carry their own skis (arms stretched out in front, palms up, drop the skis on them), and I carried everything else in a big army surplus duffel. I think having them carry skis like that also immobilized them a little, and made it less like herding cats. It was just awkward enough for them that they headed directly for the lodge, instead of their preferred option of inspecting the snowmaking pond first. When they got a little bigger, I gave them boot bags. I never let them carry my poles. That would have ended in a light saber fight. YMMV.
MM
"Everywhere I turn, here I am." Susan Tedeschi