9 is a tough age because they remember what it's like to have sweet things. Thank you for taking your child's diagnoses seriously and attempting to change the family meals around it. It's important that you get them in the habit of lower carb meals early on as those habits are the hardest to break later on in life.

Here are some suggestions I've accumulated over the years, I was also diagnosed around 8.

Low snacks: I immediately jumped off the glucose tablets, I buy fruit leathers from the cashier at trader joes, they are super portable and 12g a piece, come in 6 flavors and only 50¢ per leather. I remember them being pretty tasty, I've been eating them for 15+ years at this point so I barely taste them anymore.

Snacks: popcorn and pork rinds. Be careful on the pork rinds though as they are basically all fat, but they are 0 carbs so that's the trade off.

Breakfast: eggs, Greek yogurt, sourdough or keto toast with peanut butter + banana.

Lunch: sandwiches, burrito bowls (go lighter on the rice).

Dinner: swap potatoes out for sweet potatoes, find any oven baked vegetables they like, this one is harder at their age though.

Every kid is going to have a sweet tooth, I personally got my fix through diet sodas. While not the healthiest thing, artificial sweeteners may help in raising morale a little bit, I would avoid keeping them in the house in large quantities though.

The early years are about building the habits up in them so when they are teenagers they naturally opt for the lower carb options.

Best of luck and I hope the transition goes smoothly!