Back in the 70's and 80's people believed that if you taught a young child how to draw realistically, that you would stifle their creativity. It was generally assumed that moving from one mode of drawing to another was a natural process and that if you didn't transition it was because you weren't "talented" or "gifted" or maybe your family already had an artist in it so you really should choose something else.
Thank goodness for people who question the system, right?! Symbolic and realistic drawing are two types of drawing. Each serves a purpose and children can move between the two with absolutely no damage done to creativity.
The only side effect is they may continue to keep drawing after age nine. It's about time if you ask me.