A creature needn't be domesticated to be taught tricks
The issue might be the Handle Animal skill use Rear a Wild Animal that says
To rear an animal means to raise a wild creature from infancy so that it becomes domesticated. A handler can rear as many as three creatures of the same kind at once. A successfully domesticated animal can be taught tricks at the same time it’s being raised, or it can be taught as a domesticated animal later.
Emphasis mine. But don't let that distract you! Nothing stops an animal handler that successfully manages to befriend a non-domesticated creature from training that non-domesticated creature. The difference in Pathfinder between a domesticated creature and non-domesticated creature is that folks untrained in the skill Handle Animal can instead make Charisma checks to handle the animal to make it perform tricks it knows (DC 15) and push the animal to make perform tricks it doesn't know (DC 25—good luck!); such folks are normally out of luck, the skill Handle Animal being a trained only skill. Besides that, domesticated and non-domesticated animals are identical.
That's not to say rearing a creature so that it's domesticated isn't valuable. For example, it's a good idea to rear a wild cat so that it's domesticated and teach it the trick Down so little Billy (or a wizard) can (maybe) make a Charisma check instead of getting mauled to death. But if you find a bulette in the wild, improve its (likely quite negative) attitude toward you sufficiently, and then try to teach Mr. Bu-Bu some tricks, that's totally a thing. To be sure, a time-consuming thing (and probably an expensive and dangerous thing, too, depending on the GM's view of the granularity of the task), but you needn't worry about domesticating Mr. Bu-Bu prior to teaching him tricks. Just be sure to keep him away from little Billy until Billy's got some ranks in Handle Animal.
The Dungeons and Dragons, Third Edition skill Handle Animal made a much sharper distinction between domesticated and non-domesticated animals, for example, requiring a longer amount of time to train non-domesticated animals and providing different DCs for handling and pushing domestic and wild animals. The skill Handle Animal was simplified by the Dungeons and Dragons 3.5 revision, but the text for Rear a Wild Animal remained largely unchanged (animal or beast becoming animal), still including the now-pointless mention of taught tricks as a domesticated animal. That unchanged text made its way into the Pathfinder version of the skill Handle Animal without commentary where it sits, confusing readers for over a decade.