that's a big jump for your dd, especially when she's only 9 - what is her club expecting her to do when she's 12?
ds is now 13 and swims 6/7 times a week but his club does fewer sessions than some of his rivals' clubs who are doing up to 10 sessions a week. At 9 he was doing 3 x 1.5 hour sessions, which went up to 4 sessions when he was 10 (3 of which were 2 hour sessions)
he still really loves swimming (though so far hasn't lived up to his early promise - at 10 he was in the top 5 in the country for his best events, now he's lucky to scrape into the top 100), but being honest I have to say I think he spends too much time swimming for what he gets out of it - getting him to and from training and galas etc has a huge impact on the rest of the family too
a lot of the reason that he enjoys going swimming so much is that he sees his swimming friends who are different from his school friends - and importantly, because he goes to a boys' school, they include girls!
but if the rest of the children in your dd's squad are much older than her, that wouldn't be so important, I do wonder, however, how well the training is adapted to her as 9 year olds shouldn't be doing the same kind of sets as 14 year olds, however talented they are.
Can you talk to your dd's coach and explain your worries and maybe see if she can do 4 sessions a week for a while and see how she gets on. After all, Caitlin McClatchey (commonwealth gold medallist) only did 3 sessions a week until she was 16 and decided to take it a bit more seriously and it didn't do her any harm!
dd is 7 and has started swimming at ds1's club - she's currently doing 2 sessions a week and to be honest I'm really hoping she won't want to take it as seriously as ds1 as she wants to do so many other things - ballet, gymnastics, cycling, horseriding etc and there's only so much time