Need help removing a T9 screw please!

Some of those devises do, depends on the screw. other meathods are using a dremel cutting wheel to cut a slot for a flathead or using a drill bit to drill it out. Was a non-t9 bit used previously? being sure to use the correct bit and torque will help eliminate head stripping.

i am a mechanic and have to deal with this problem on the daily
also i work on toys and know the difficulty of screws in small places
attached to fragile electronics
best way i can see if none of those fancy removing tools work which most do not.
get a very sharp drill bit which is just smaller than the diameter of the screw(not the head) drill squarely down through the screws center. once youve reached the bottom all that will be left is the threads of the screw in its cooresponding threads. if you did not damage the "nut" (female threaded insert) that the screw goes in then you can pick what remains out of there and retap(you must buy the exact size tap of the screw you are trying to remove).
if you did damaged that section which is very likely then you have the option of oversizing the hole and buying a heli coil set which replaces the original threads after an oversize bit makes room.
finding a heli coil set in that size may be tricky but they are out there
good luck

You should have gotten a T9 screwdriver 😀 I think they are under $4.

Well, if the screw is dispensable, you can try super gluing or epoxy something (T shaped) on top of the head of the screw and twist it once its stuck together.