Do you need the logbook endorsements for Class B, C and D airspace if you have a Commercial Pilot Certificate with instrument rating but are operating as a sport pilot with your driver’s license as your medical?
No, holders of higher-level pilot certificates are exempt from the requirement for an airspace endorsement when operating at the sport pilot level. You have already had the appropriate training and have demonstrated your ability when being tested for the higher-level certificate. You simply need a current flight review recorded in your pilot logbook, just as you did when you were flying at the higher certificate level.