I'm an introverted 9 who actively creates peace and harmony.
This has little to do with being 9w1 or 9w8, Introversion or Extroversion, and everything to do with mental/emotional health.
When fixated, I literally didn't have enough mental focus or energy to do anything except the bare minimum to get people off my back. As I become less fixated, the mind clears up, and suddenly I can see active uses for the self-defensive skills I have as E9, to help people. I.e. Empathy--active merging to understand people from their perspective, true attentiveness, calming influence, etc.
I've known introverted and extroverted 9s, energetic versus sluggish 9s, in-the-background versus front-and-center 9s. These differences are because we are different people not an Enneagram type. E9 is just the set of obsessive thoughts and habitual emotional tendencies that we adopted, which prevents us from seeing and dealing with reality as it really is.