A geometry problem by Mark Vincent Esmeralda Mamigo

A triangle with sides 7, 8, and 9 is being revolved with the angle bisector to the side 9 as its axis. If the volume of the solid can be expressed in the form $\dfrac{\pi a\sqrt{b}}{c}$ in the simplest form, find the sum of the digits of $\dfrac{ac}{b}$ .