First at 9 he may truly not know why. Its part of being a kid.
As the skills become harder it is likely going to take longer. The conditioning while not a favorite or necessarily fun is going to become all the more important. He will have to come to terms with this to keep going.
And yes he doesn't "yet"
Take him back....................... to past "yets" and how he needs to practice.... and keep at it....
Way back, video if you can. These days most of us have video.
Of things he does now without even thinking about, but he had to learn.
Somethings I do/did with mine.
Show her crawling videos reminding her there was a time she couldn't even walk. And then when she started walking how it is not quite the walking/running she currently does.
Her first ugly ugly cartwheels, so I ugly I wasn't sure she would ever get them.
Her first attempts at reading/speaking. Things like when she called toilet paper, roller paper.
I quickly ask her what 2+2 is... And she immediately says 4. Hmmm there was a time you had think and use your fingers.
Did you get better at all those things?
Her; Yes
How?
Practice (insert eyeroll now)
Me; And patience (insert smile)