I have found that some younger kids are far more responsible and intelligent than I have given them credit for - especially when their parent keeps much more exciting animals like snakes.
I took a Jacky from the wild when I was 8 or 9, and bought my first beardie not long afterwards.
Depends what your daughter is after really. Will 'Bluey' the BT still have her fascinated in a year? 2 years? (They seem to grow up so quickly at that age).
When I was a kid, I liked bluies coz they were cute and all, but they were never really interesting for me. They look similar all over, they're smooth, and the only thing that they had going for them (in my mind) was their blue tongue!!! lol
Personally, I would go a beardie, but I am COMPLETELY bias cos I would never buy a bluie for the world now that I have these guys (made that decision at about 10yo lol), and I have always found them that much more interesting and interactive.
Also, I have had HEAPS of parents buy beardies for their kids and they were younger than 9. I'm sure that, with your daughter being raised with the wonderful world of herps, she is responsible with them and has a much better head start on their care than other kids do. I say go for whatever you think she would still love as she continues to grow, rather than something that might only satisfy her curiosity for a year
Good luck hun
Bex