Difficult# Strategic Solving

SATMAT-GG4KJS

$ \begin{cases}\frac{2}{9}x-\frac{1}{2}y=2 \\\\Cx+\frac{2}{3}y=\frac{1}{3}y-2Cx \end{cases} $

In the system of equations shown above, the solution of the system has a $ y $ -value of -6.

Find the value of $ -9C\\\ $.