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I like to collimate my SCT's in the day with an artificial star.
The C9.25 would probably need to be done outside on an overcast day, unless you have access to a hall where the light source can be positioned far enough away from the scope. You can take your time, use high power and get the first in-focus diffraction ring even. Then check the collimation on a star to see if mirror movement has changed it - tweak if necessary.
The light source only has to be far enough away to form an image, unlike testing for optical quality where you need to be concerned about introducing spherical aberration.
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