I'm pretty sure you have to lower the steering rack to get the U joint off, but I think you can leave it all connected and just remove the jacking pad underneath it and the two bolts that connects it up to the big cross-member. Before anything, did you try loosening and tightening the u-joint to see if it gets any tighter?

I would use a sharp scribe to mark lines on the top and bottom of the u-joint and also make sure not to turn the steering wheel much at all, if you are off one turn you can snap the safety bag wire and the srs light will come on.

Once it's off I'd look for damage to the inner spline, the steering column itself could be worn out too I suppose, but the U-joint seems like it's made out of softer aluminum. I'm just brainstorming, but maybe you could get away with adding a strip of some aluminum foil to fill the gap of the worn away spline. Best of luck.