how to extract x,y coordinates from OpenCV "cv2.keypoint" object?

point.pt is a tuple(x,y)`.

So,

x = point.pt[0]
y = point.pt[1]

or,

(x,y) = point.pt

You can use:

import numpy as np

pts = np.float([key_point.pt for key_point in kp]).reshape(-1, 1, 2)

pts will be an array of keypoints.

OpenCV provides a function for this. You can run:

pts = cv2.KeyPoint_convert(kp)