To find the slope \( m \) of the line that passes through the two points \((6, 6)\) and \((9, 5)\), we use the formula for the slope:
\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]
Here, \((x_1, y_1) = (6, 6)\) and \((x_2, y_2) = (9, 5)\).
Now, substituting the coordinates into the slope formula:
\[ m = \frac{5 - 6}{9 - 6} = \frac{-1}{3} \]
Thus, the slope of the line that passes through the points \((6, 6)\) and \((9, 5)\) is
\[ \boxed{-\frac{1}{3}}. \]