Have you looked at any of the ground connections?
Probably ok at 10.9 volts. You could try boosting that voltage by jump starting it off a running car or truck and see if that makes a difference. maybe even try connecting the jumper cable ground to the Grizzly engine block (acts a redundant ground/different ground path).tried with spark plug installed.... Reading 10.9v while cranking... Good or no good??
CDI maybe?? Could it still be the CDI even if it spareks fine with the pullstart??