Ryder wants to do EVERYTHING that his dad does. When Kit gets home, NOTHING else exists. Anything his dad does, he wants to be part of.
Case in point:
Yard work.
Sitting anxiously (in his dad's hat) while Kit edges. It's the one part of yard work that we have to keep him at a distance with...
Then it starts with him wanting to push the mower himself, but he concedes to let his dad hold him:
Which quickly leads to pulling out the backpack:
Hey, anything that allows him to be with his dad...