The fix is irrelevant to my question, but was the crack already there before you put the nut on or did you possibly screw the nut on too tight and caused the split? I only ask so you can verify that you are not pinching the stock with the bolt/nut. Otherwise, if you repeat the tightening it may/will just crack again.
As to shooting, may aftermarket stocks don't even have the crossbolt so I don't think you'll hurt anything continuing to shoot it.
On repair, given the oils in the wood gluing it may or may not hold without first removing the oils from the stock. One thing I use a lot to remove oils, cosmoline, etc. is brake cleaner. It dissipates the oils well, dries without leaving a residue, and does not harm the metal or the wood. You do have to re-oil whatever you are working on afterward though.
Here is one method you can try. Someone else may have another suggestion that may be better, but here is my $.02 worth.
1. remove the stock and remove the cross-bolt.
2. with a flat blade screw driver, putty knife, or similar separate the crack just enough to then take a spray can of brake cleaner(use the nozzle tube) to clean out the crack area. It will dry fast.
3. After a few minutes, with the crack still separated and from the inside of the stock, run some really good wood glue down into the crack. You may want or need to use a toothpick or similar to get the glue down into the crack better.
4. remove the screwdriver or whatever you used to separate the crack and then clamp the stock to press the crack together(don't over tighten or you may indent the stock). Leave it for 24 hours.
5. After 24 hours, remove the clamp and with a razor blade gently remove any excess hardened glue.
6. As needed lightly scrub with #0000 steel wool then oil up(tung oil or linseed oil works real well) the outside of the stock to match up the finish. You may not need to do anything if you are lucky.