\[ y'(x)=-\frac {8 (a-1) (a+1) x}{a^8 x^6-4 a^6 x^6-3 a^6 x^4 y(x)^2-2 a^6 x^4+6 a^4 x^6+9 a^4 x^4 y(x)^2+6 a^4 x^4+3 a^4 x^2 y(x)^4+4 a^4 x^2 y(x)^2-4 a^2 x^6-9 a^2 x^4 y(x)^2-6 a^2 x^4-6 a^2 x^2 y(x)^4-8 a^2 x^2 y(x)^2-a^2 y(x)^6-2 a^2 y(x)^4-8 a^2+x^6+3 x^4 y(x)^2+2 x^4+3 x^2 y(x)^4+4 x^2 y(x)^2+y(x)^6+2 y(x)^4-8 y(x)+8} \] ✓ Mathematica : cpu = 4.88308 (sec), leaf count = 13
\[\left \{\left \{y(x)\to \left (a^2-1\right ) c_1\right \}\right \}\]
✓ Maple : cpu = 3.314 (sec), leaf count = 80
\[ \left \{ {\frac {y \left ( x \right ) }{ \left ( a-1 \right ) \left ( a+1 \right ) }}+4\,{\frac {1}{{a}^{4}-2\,{a}^{2}+1}\sum _{{\it \_R}={\it RootOf} \left ( {{\it \_Z}}^{3}+2\,{{\it \_Z}}^{2}+8 \right ) }{\frac {\ln \left ( -{a}^{2}{x}^{2}+ \left ( y \left ( x \right ) \right ) ^{2}+{x}^{2}-{\it \_R} \right ) }{3\,{{\it \_R}}^{2}+4\,{\it \_R}}}}-{\it \_C1}=0 \right \} \]