$8.27 \quad \log _{2}\left(1+\log _{\frac{1}{9}} x-\log _{9} x\right)<1$.

Translate the above text into English, please retain the original text's line breaks and format, and output the translation result directly.

$8.27 \quad \log _{2}\left(1+\log _{\frac{1}{9}} x-\log _{9} x\right)<1$.
8.27 Noticing that $\log _{\frac{1}{9}} x=-\log _{9} x$, we can rewrite the given inequality as

$\log _{2}\left(1-2 \log _{9} x\right)0 \quad$ (the inequality $\log _{2}\left(1-2 \log _{9} x\right)0$ is automatically satisfied).

Answer: $\left(\frac{1}{3}, 3\right)$.