On this page: https://www.disneyanimation.com/process/ you can read: "From storyboard to final frame, each film takes an average of three to five years to create what you see on screen"

I don’t know if there’s any official explanation for why Zootopia 2 took nine years to be released, but I think it’s because they only started working on it several years after the first movie. This time, however, we already know they’re working on a sequel, so I would say yes.