\[ \boxed { \left ( {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) \right ) y \left ( x \right ) - \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}+ \left ( -1+ay \left ( x \right ) \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) -y \left ( x \right ) \left ( 1+y \left ( x \right ) \right ) \left ( {b}^{2} \left ( y \left ( x \right ) \right ) ^{2}-{a}^{2} \right ) =0} \]
Mathematica: cpu = 104.391256 (sec), leaf count = 55 \[ \text {DSolve}\left [-y(x) (y(x)+1) \left (b^2 y(x)^2-a^2\right )+(a y(x)-1) y'(x)+y(x) y''(x)-y'(x)^2=0,y(x),x\right ] \]
Maple: cpu = 4.383 (sec), leaf count = 91 \[ \left \{ y \left ( x \right ) ={\it ODESolStruc} \left ( {\it \_a},[ \left \{ \left ( {\frac {\rm d}{{\rm d}{\it \_a}}}{\it \_b} \left ( { \it \_a} \right ) \right ) {\it \_b} \left ( {\it \_a} \right ) -{\frac { {{\it \_a}}^{4}{b}^{2}+{b}^{2}{{\it \_a}}^{3}-{{\it \_a}}^{2}{a}^{2}-{ \it \_a}\,{\it \_b} \left ( {\it \_a} \right ) a-{\it \_a}\,{a}^{2}+ \left ( {\it \_b} \left ( {\it \_a} \right ) \right ) ^{2}+{\it \_b} \left ( {\it \_a} \right ) }{{\it \_a}}}=0 \right \} , \left \{ {\it \_a} =y \left ( x \right ) ,{\it \_b} \left ( {\it \_a} \right ) ={\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right \} , \left \{ x=\int \! \left ( {\it \_b} \left ( {\it \_a} \right ) \right ) ^{-1}\,{\rm d}{ \it \_a}+{\it \_C1},y \left ( x \right ) ={\it \_a} \right \} ] \right ) \right \} \]