Let \( f(x)=x^{2}+9 \), \( g(x)=\dfrac{x}{x-9} \) and \( a=f o g(10),\, b=g o f(3) \). 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:
