I made this support rings for my C9.25 that has a Dew Heater Ring on it.  Needed something that would not require any cutting or alteration of a collimation mask.    The mask I made it for is this one:

https://makerworld.com/en/models/1383402-celestron-edgehd-c925-tri-bahtinov-mask?from=search#profileId-1432273

It does work for a Bahtinov mask that I have also.

Printed it on a Snapmaker U1 with the following settings:

PLA

Walls = 4

Infill = 15%

Pattern = Grid

Print upside down (inner ring on build plate) with supports

I hope this is a solution for fellow C 9.25 owners - if you have other SCT's with the dew heater ring, please feel free to alter this to meet your needs.

Clear skies!