Legal Question in Business Law in Illinois

By using "professional" in your question, you indicate that you believe some sort of state certification is required. In my opinion, no. Depending on your area of residence, you may need a business license and need to make contact with the Department of Revenue to set up retail sales tax collection. Be careful where you "install" cameras. If the premises is not owned by the customer, then you could find yourself charged criminally for obtaining surveillance of a person without consent.