Employee stealing customers. Does employer have recourse?

Maybe.  Someone would need to review the terms of the non-compete and compare it to the alleged actions of the employee.  One would also need to understand the facts and circumstances relating to when the employee executed the non-compete to determine if its enforceable.  Even without a non-compete, employees have a common-law duty of loyalty to their employers and should not "convert" potential customers of the employer for their own benefit and profit.