\[ \boxed { y \left ( x \right ) \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}+2\,x{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) -9\,y \left ( x \right ) =0} \]
Mathematica: cpu = 0 (sec), leaf count = 0 \[ \text {Hanged} \]
Maple: cpu = 0.640 (sec), leaf count = 209 \[ \left \{ -{\frac {{\it \_C1}\,x}{2} \left ( -x+\sqrt {{x}^{2}+9\, \left ( y \left ( x \right ) \right ) ^{2}} \right ) \left ( {\frac {1}{y \left ( x \right ) } \left ( -x+\sqrt {{x}^{2}+9\, \left ( y \left ( x \right ) \right ) ^{2}} \right ) } \right ) ^{{\frac {2}{7}}} \left ( x \sqrt {{x}^{2}+9\, \left ( y \left ( x \right ) \right ) ^{2}}-{x}^{2}- \left ( y \left ( x \right ) \right ) ^{2} \right ) ^{-1}{\frac {1}{ \sqrt [7]{{\frac {1}{ \left ( y \left ( x \right ) \right ) ^{2}} \left ( 2\,{x}^{2}+2\, \left ( y \left ( x \right ) \right ) ^{2}-2\,x\sqrt {{x}^ {2}+9\, \left ( y \left ( x \right ) \right ) ^{2}} \right ) }}}}}+x=0,{{ \it \_C1}\,x \left ( x+\sqrt {{x}^{2}+9\, \left ( y \left ( x \right ) \right ) ^{2}} \right ) \left ( {\frac {1}{y \left ( x \right ) } \left ( -x-\sqrt {{x}^{2}+9\, \left ( y \left ( x \right ) \right ) ^{2}} \right ) } \right ) ^{{\frac {2}{7}}} \left ( x\sqrt {{x}^{2}+9\, \left ( y \left ( x \right ) \right ) ^{2}}+{x}^{2}+ \left ( y \left ( x \right ) \right ) ^{2} \right ) ^{-1}{\frac {1}{\sqrt [7]{{\frac {1}{ \left ( y \left ( x \right ) \right ) ^{2}} \left ( x\sqrt {{x}^{2}+9\, \left ( y \left ( x \right ) \right ) ^{2}}+{x}^{2}+ \left ( y \left ( x \right ) \right ) ^{2} \right ) }}}}}+x=0 \right \} \]