The hyperstar turns your C9.25 into an f/2 scope doesn't it? The relatively short focal length then means the guidescope mounting is not critical.
I've got an Orion Starshoot 50mm finder guider on my C8.
http://www.bintel.com.au/Astrophotog...oductview.aspx This one. It's mounted directly to the finder shoe screwed into the C8. At f/10 I get oblique stars as 2000mm is too much of a focal length to expect to work with such a small guider. At f/6.3 it works quite well. At f/2 it would work perfectly with the guider having a very similar focal length to the scope itself.