I'm a cardiologist. At age 9, kids really don't know what they want to be. She is at least 25 years away from being a fully practicing physician- who knows what the practice of medicine will be like then? Alot of fields, including cardiology and surgery, can offer a good work-life balance.
These threads offer up a general theme though for some kids who grade skip- when they get into the higher grade levels, like high school, the amount of busy work associated with taking Honors/AP classes can be overwhelming if they are alot younger than their classmates.