I need 9 colors of the same exact particle object, but I don't want to create 9 particle objects for that. Instead I've been trying to change the color of the one particle object at runtime or when the object is created. Couldn't find anything on it for now. Is there even a way to do this?
Try tint.
I just tested by changing RGB on a Button click - works fine.
Just set the 3 parameters of the RGB values of the particle object to whatever you want.
Alternatively, create your own particle system using sprites. You can then simply change image frame for different colours.