The 25-9 is an updated 25-5, has the endurance upgrades, and is a fine gun. I wouldn't cut the barrel down though. Instead, I would look for a different gun. They didn't make all that many of these guns with the upgrades.
I am a huge fan of the .45 Colt. It will make a great hog gun. Short barrels are for defense, and trail guns. If you plan on hunting hogs with it, leave it as is. You'll be able to more accurately place your shots, and you'll gain some useful velocity over a snubbie.
Read this on the .45 Colt-
http://handloads.com/articles/default.asp?id=12