If a right circular cone, having maximum volume, is inscribed in a sphere of radius $3$ cm, then the curved surface area (in $\mathrm { cm } ^ { 2 }$) of this cone is :\\
(1) $8 \sqrt { 2 } \pi$\\
(2) $6 \sqrt { 2 } \pi$\\
(3) $8 \sqrt { 3 } \pi$\\
(4) $6 \sqrt { 3 } \pi$