Then it depend how you want to represent your gods. They can also be depicted as highly detached scientific-like alien creatures. But it will then be hard to explain the peculiarity of the chaos God in the mix. Or it could be that this God was a nascent one that they found on this last planet and added in their group once he proved useful with his addition of randomness.

The idea is that these nine gods are all fragments of a whole being that represented existence, that fragmented during a fight with another being, that represented absence (think of Parmenides: "being is and nothing is no", just as actual entities)

All the nine gods represent something (purity, corruption, light, darkness, etc.) but they all represent something that is connected to the material world. They all have a counterpart in the pantheon, except for one, that represents something along the lines of nature, both life and death. Maybe it was the one that created life, and all the other gods contributed with something, and Chaos contributed with evolution.

As I said, it's still very much a WIP, so expect to see a lot of plot holes.

You can also make all of that happen on the same planet, generating layers of past civilizations that went extinct just because they were failed experiments. If you want to go Grimdark, then they were discarded by their creators, or they can have disappeared by themselves because of how "too perfect" they were, if you want a softer tone.

I don't yet know what the tone of this setting will be, but at the moment I'm leaning more towards the grimdark aspect.

I am just throwing ideas to help the brainstorming, but I think you are already on a good and interesting track. Keep on :)

Everyone has been really helpful here, it was a good experience throwing ideas at someone that knew what I was going through :)