If a 9-month-old baby has not urinated for 5 hours, it is recommended to wait a little longer and observe. Sometimes, during a fever, the body may not produce urine for a few hours. It is advised to not worry at the moment, but if the baby still has not urinated by tonight, it may be necessary to consult a medical professional. If there are any other symptoms present, such as fever, cough, shortness of breath, or extreme fatigue, it is important to seek medical advice promptly. Visiting a healthcare professional or using a recommended online resource for guidance can help determine the next steps.