Ответ:

\[\frac{x^9}{(x^3)^4}=\frac{x^9}{x^{12}}=x^{-3}.\]

\[x^{-3}=\left(\frac{2}{3}\right)^{-3}=\left(\frac{3}{2}\right)^3=\frac{27}{8}.\]

Ответ: \(\frac{27}{8}\).