Take it to the shop. You can take a small bit and drill a hole at the end of the split and it will stop the crack.
If it emanates from an existing hole, such as a thumb, finger, or weight hole, then plug that hole AND the crack (including the very small drillout you used to stop the crack), then redrill the thumb, finger, or weight hole you had there originally.
If it is just a crack that does NOT come from an already existing hole, then just drill both ends of the crack with the small bit, and then plug the crack AND the smaller holes.
Had a ball start to crack on me and I did this. Went on to shoot an 800 with the ball, and still have it several years later, with no further problems.
