That would be the volume of the total shape minus the volume of the center.
V=(4πR^3)/3-(4πr^3)/3
V=(4π/3)(R^3-r^3), since R=9/2=4.5 and r=4/2=2 we have:
V=(4π/3)(4.5^3-2^3)
V=(4π/3)(91.125-8)
V=(4π/3)(83.125)
V=332.5π/3 cm^3
V≈348.19 cm^3 (to nearest hundredth of a ml or cubic centimeter)