I actually think that if you've got to get T1 as a child, then 8 or 9 is a good age to get it. My heart bleeds for the parents of preschoolers or even pre-talkers who have to cope with managing the blood sugar of an infant who doesn't yet have the ability to be rational, and teenagers with a new T1 diagnosis have to cope with both stresses at once. (Not sure that being a teenager isn't worse than having T1, but it does have the massive advantage that you eventually stop being a teenager.)
At 9, your daughter will soon be doing her own injecting, carb counting and insulin calculations, and probably soon be better at it than you are. Just remember to be there if she occasionally gets overwhelmed and needs to step back for a bit. I was diagnosed 51 years ago, at 8, and I definitely agree with
@Rokaab that the tech available now makes T1 not only much easier to handle but also much much less likely to lead to long term health issues. (And I'm still alive and well with all limbs and organs intact and working.
)
Yes, it can see overwhelming on first diagnosis, but you've got plenty of time to learn to handle it (I'm still learning after half a century.)
Lots of virtual hugs. There's usually someone on here to reply if you ever have a question or just want some sympathy. Good luck.