I bought a '99 Cherokee with 120,000 miles on it and when I'm on the freeway the steering wheel needs correction a lot to center it. I'm used to small cars with rack and pinion quick steering though. Is it normal for these Jeeps to have loose steering?

 

Common....but not normal. Check your track bar bushings, ball joints, tie rod ends and so forth. And never expect it to handle like a sports car lol.
Does it wander back and forth?

 

To keep it centered in the lane at 70mph I have to keep correcting it, if i didn't it would leave the lane on either side and I had it aligned recently. If I moved the steering wheel as much on my wife's 2010 Forester it would change lanes, but the same input on the Jeep's wheel just keeps it in the lane.

 

Idk what to tell you friend. Mine wanders and has a bad dead spot in it which causes me to overcompensate. The tre's have horrible roll in them and my frame side track bar bushing is shot. I just ordered JCR's 1-ton OTK kit and a new bushing from Full Traction. Hopefully this cures it.

 

Not normal at all. Something is worn out either in the steering or the ball joints. If that's all tight, maybe the alignment is toed way out.