I’ve found a fix for hot pixels on my HDX900 and i assume on my SDX900. i haven’t try the SDX yet.
To get into the service menu, press and hold the ‘ light button and the hold button ‘ on the side of the camera then push the menu button on the front of the camera (at the same time). Hold for a couple of seconds and the menu will appear. scroll to ‘ defect setting ‘ go into it, and then scroll to’ all data clear’. clear data, then exit menu. in my case a bunch of hot pixels appeared. Black balance ( it only took one for me ) and all the hot pixels cleared including the one i tried a hundred black balances on. Good luck…Daron