An algebra problem by حسن العطية

Algebra Level 2

If $\dfrac { { a }^{ 2 }-\dfrac { 1 }{ { b }^{ 2 } } }{ { b }^{ 2 }-\dfrac { 1 }{ { a }^{ 2 } } } =9$ , then what is the value of $\left| \dfrac { a }{ b } \right|$ ?

and $\left| ab \right| \neq 1$