I was wondering is it hard to change the o rings for the oil filter adaptor, i have a 1996 Jeep Cherokee Sport 4.0L

Here is a good vid on how to..

Not really, other than the torx screw was put on by King Kong. Clearance is a bit of an issue to get a extension of some type on the wrench to loosen it. I sacrificed one end of a box wrench and then slide on a 15" piece of 3/4" galv pipe over it and approached it from below the Jeep. I also used some fine wire to "wire" the torx bit to the wrench as the angle of the torx screw on the adapter is facing down just enough that gravity won't let the bit stay in place by itself. Four of five precisely chosen publicly offensive words, bit of donated hand skin, disgruntled looks at the spouse and other spectators and viola, done in a snap..

Perfect description except you left out the fact that King Kong used LocTite on the threads!!!!

I prefer to use the pkg. of O-Rings made for it from Jeep just a few cents more as I remember.

1)Get your o ring set from jeep as mentioned.
2)Clean the torx hole with pick & carb cleaner completely.
3)warm jeep up.
4)working from underneath remove torx bolt.
5)replace all 3 o rings,& install bolt after welding nut on bolt.

#4 is the hardest part. Make sure you clean it throughly & have the bit seated all the way in. You will not be able to fit a bit & wrench due to the motor mount being in the way. You will need a shorty bit or something like I made (see photo). There is a thread showing a bit set available from harbor freight or Home Depot on this forum.
Make sure you grease o rings before install.
weld a nut on the bolt before install (see photo).
I could not get the bolt out until I made the tool.
Good luck.

Pic