9. \( 13 c^{2} d+c d^{2}-7 c^{2} d-11 c d^{2} \)

To simplify the expression \( 13 c^{2} d + c d^{2} - 7 c^{2} d - 11 c d^{2} \), we start by combining like terms. The terms containing \( c^{2} d \) are \( 13 c^{2} d - 7 c^{2} d \), which gives us \( 6 c^{2} d \). For the \( c d^{2} \) terms, we have \( c d^{2} - 11 c d^{2} \), which simplifies to \( -10 c d^{2} \). Therefore, the final simplified expression is: \[ 6 c^{2} d - 10 c d^{2} \]