Hi Mark,
I assume you have a Celestron 9.25 SCT? Google search shows:
2350 mm focal length (f/10)
2350mm/23mm=102x magnification view (focal length divided by the eyepiece focal length)
You probably want something that gives around ~130x - 150x as most nights you will be limited by the seeing conditions. A barlow will be useful as well to double your eyepiece set. I find it not that often I can push beyond 220x due to the seeing conditions.
Also since you have a SCT, you will need more time to cool it down as it is sealed to improve viewing.
Its a slippery slope when it comes to eyepieces, you can spend a lot
. This becomes apparent with wider degrees of view of eyepieces.
Hope it helps.
Regards,
Mel