I'm not sure if Jackie is 9 or 11 years old but does it really matter because her voice is extraordinary.
Li-sa-X (in this video she's 8 years old) kills it on the guitar. The best part is at the 1:47 mark she looks at the camera with this sweet, innocent smile but reading in between the lines I'm pretty sure that smile says "that's right, I rock."
Tsung Tsung is five. FIVE! And the kid has flair.