To find the distance \( d(A, B) \) between the points \( A(2, -6) \) and \( B(2, 3) \), we can use the distance formula:
\[ d(A, B) = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} \]
Here, the coordinates of point \( A \) are \( (x_1, y_1) = (2, -6) \) and the coordinates of point \( B \) are \( (x_2, y_2) = (2, 3) \).
Substituting the coordinates into the formula:
\[ d(A, B) = \sqrt{(2 - 2)^2 + (3 - (-6))^2} \]
Calculating the differences:
\[ d(A, B) = \sqrt{(0)^2 + (3 + 6)^2} \] \[ d(A, B) = \sqrt{0 + 9^2} \] \[ d(A, B) = \sqrt{81} \] \[ d(A, B) = 9 \]
Thus, the distance \( d(A, B) \) is:
\[ \boxed{9} \]