\[ 8 y''(x)+9 y'(x)^4=0 \] ✓ Mathematica : cpu = 0.0835306 (sec), leaf count = 92
\[\left \{\left \{y(x)\to c_2-\frac {1}{3} \sqrt [3]{-\frac {1}{3}} (9 x-8 c_1){}^{2/3}\right \},\left \{y(x)\to \frac {(9 x-8 c_1){}^{2/3}}{3 \sqrt [3]{3}}+c_2\right \},\left \{y(x)\to \frac {(-1)^{2/3} (9 x-8 c_1){}^{2/3}}{3 \sqrt [3]{3}}+c_2\right \}\right \}\] ✓ Maple : cpu = 1.227 (sec), leaf count = 51
\[\left \{y \left (x \right ) = c_{2}+\left (c_{1}+x \right )^{\frac {2}{3}}, y \left (x \right ) = c_{2}-\frac {\left (c_{1}+x \right )^{\frac {2}{3}} \left (1+i \sqrt {3}\right )}{2}, y \left (x \right ) = c_{2}+\frac {\left (c_{1}+x \right )^{\frac {2}{3}} \left (i \sqrt {3}-1\right )}{2}\right \}\]