Hello. Glad you're doing your research
I would say absolutely, yes, a Syrian would be a good choice for her first pet. They are somewhat larger to handle and, in my view, easier to tame. And to form a bond with. Some people may disagree! But generally Syrians are seen as the easiest first pet and taming and bonding should be much easier. All hamsters can be fast, but a tamed Syrian is, again in my view, less fast and much easier to handle and interact with. Some of them even go to sleep on you. They have their fast times of day and their slower times of day.
Where to get one is the tricky thing. Apart from rescues and adoptions, there are mainly only pet shops. There are official breeders but it can be hard to find one from a breeder - breeders seem quite scarce these days. And by breeders I mean proper breeders who are registered with the National Hamster Council. Beware of people advertising who call themselves breeders. Breeding genetics is a very specialised thing.
I would say first port of call could be a rescue - they have often tamed the hamsters already and given them good care and regular handling. And they often have litters of babies as well (taking in a pregnant hamster eg). There are also private adoptions on places like Gumtree and Pets 4 Homes but the hamster may have already had a not so good start and be harder to tame for your 9 year old. You maybe need to go with your instinct with that. Some people are genuine (ie a well cared for hamster but child is allergic eg), some, the hamster is terrified of hands after inappropriate handling by small children who've got bored.
Whereabouts are you? Uk? Region? To see where the nearest rescue is. I know of a good one in the North/Midlands.