A hyperbola has a vertical transverse axis of length 6 and asymptotes of $y = \frac{3}{8} x + 9$ and $y = -\frac{3}{8} x + 1$. Find the center of the hyperbola, its focal length, and its eccentricity.

The center of the hyperbola is (, ).

The focal length is .

The eccentricity is .