If a 9-month-old baby has a fever of 37.8 degrees, it mainly depends on the child’s condition. If the child is in good spirits and can eat and play, you can leave it alone and continue to observe. If the temperature reaches 38.5 degrees and the child is still in good condition, you can first physically lower the temperature, such as feeding more plain water, or rubbing the body with warm water, or taking a bath with warm water can be. If the child is not in good condition and the temperature rises above 38.5 degrees, it is recommended to give antipyretic drugs such as acetophen or ibuprofen. If the child is in a very bad state, more drowsy, irritable or crying, or accompanied by other obvious symptoms, such as vomiting, diarrhea or coughing, it is recommended to go to the hospital promptly.