Frobenius & Special Functions · Medium problem

The equation $x(x^2 + 9)\,y'' + y' + xy = 0$ has a regular singular point at $x = 0$. Frobenius theory guarantees that the series solutions about $x = 0$ converge for $0 < |x| < R$, where $R$ is the distance to the nearest other singular point (in the complex plane). Find $R$.