Not a 9 month old IMO , way too small.
If it is indeed 9 months old it's very malnourished and is going to need lots extra high quality live insects and plenty UVA and UVB , and a good basking setup and a long day cycle (I'd recommend 3 live insect feeds per day and at least 10%
UVB light source and 15 hour days and a basking spot at about 40degCelsius and night time heating to keep it warm overnight so it can have a boost in its growth).
Nonetheless , it is still going to become a very good pet, and will likely lead a healthy and happy life if your husbandry is good and it's given what it needs , it'll never grow to be a large as most other central beardies (it'll never catch up size wize) but that's OK.
I though she might be a rankins but on double checking the images you provided the crest ridge is indicative of a central beardie.
Are you sure they said she was 9 months old and not 9 weeks old ?
If I'm on the money and she is 9 weeks old , as I strongly suspect based her size, she's doing fine.
(Schedule three high quality live insect meals per day = as many bugs as she wants each feed, lights on 15 hours per day , keep her warm overnight (warmer than 24 degCelsius).)
In either case it's much more important at her age to get lots of high quality live insects than greens and vegs .
I suggest you feed her
>>> phoenix worms (calcigents) , don't need to be dusted with calcium
>>> small sized silkworms (about 1.5inches long) , don't need to be dusted with calcium
>>> 1/3 sized gut loaded crickets (I think these are called "small" crickets by most sellers) who need to be dusted with calcium or similar sized roaches.
A comparisons :
Smallest 9 month old central beardie I've seen was 210g and she was considerably bigger than the one you've shown us.
My Puff and Rex were both 282g at 9 months old, Peppa was 368g and Toothless 292g at 9 months old.
At 9 weeks old Peppa was 32g, and Toothless was 27g. Puff and Rex were both 23g.