I'd go the C9.25.
The EQ6 will have no troubles with it. They are light for their size, generally speaking they are held in high regard among imagers for having good/great even the occasional "extraordinary" optics..
They will allow you a good focal length for hunting galaxies, the option of the 6.3 reducer for wider field work... To be honest, I think either the C8 or C9.25 would be great.... But in my opinion, Aperture always wins out... (Check my signature
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