I don't think any of us thinks our 9 year olds are no longer children. But they are changing and growing up and 9 and 10 seem like a long ways from 5 and 6. Because they have changed SO much.
These years are here for a reason, so you don't watch your kid jump from a missing toothed 6 year old straight to a hormone filled 16 year old. It's much more gradual than that so seeing these little signs makes it real, as in, yeah my kid's getting older, he's not really THAT far from being a teen.
I very distinctly remember my teen years and have no desire to enter that on this side, any time soon. But it's like anything else, it's a stage we gradually get to and when we do, we're a little more prepared for having survived these tween and pretween years.
My son very abruptly (at least to me) jumped from watching Spongebob and Scooby Doo to watching the tween shows. And there's nothing wrong with that, it's perfectly natural, even if every family doesn't follow this path. I just hate the vibe I'm getting from this thread that unless your still plays with dolls and blocks at 9, you're doing something wrong or pushing them to grow up or something.
For me, my kids develop at their own pace. My 9 year old is who he is, as a 9 year old. I'm certainly not pushing him into chasing girls or shaving or anything else. He's gorwing up at his pace, not anyone else's.