There is no easy way to get projectile coordinates if you use CreateProjectile function.
A year ago, i experimented with object functions to achieve that, but failed.
There are three particular functions to measure projectile position based on my logic, the first one is ObjectFindInArea to identify all objects around us, the second function is ObjectIsInAreaXYZ to limit the scope, and the third function is ObjectIsModel to recognize the projectile itself.
I failed because i can't manage ObjectIsModel function to work as there is no any reference that i can use to utilize this function. I was just guessing what its function arguments are, it crashed when i tried ObjectIsModel(OBJ, PROJ_ID). For that reason, i can't identify the projectile i want, so i can't retrieve its position.
That's the end of my story for finding projectile position lol.
I hope this old experiment will be useful for further research or experiment.