Let $f(x) = x^{2} + 9$, $g(x) = \dfrac{x}{x - 9}$, and $a = f \circ g(10)$, $b = g \circ f(3)$. If $e$ and $l$ denote the eccentricity and the length of the latus rectum of the ellipse $\dfrac{x^{2}}{a} + \dfrac{y^{2}}{b} = 1$, then $8e^{2} + l^{2}$ is equal to: