At least unless it was agreed upon on session 0 or was included into your "social contract" in a clear way.
Animal Companion is a class feature. Making it work against the character removes his agency over his own class features. This does not sound right, does it? Mind control spells are something that many tables ban outright, and most tables use sparingly. It is one thing if enemy prevents something from working (like counterspelling Fireball), it is totally another if he makes it work against the player (like making fireball turn around and hit the caster).
Handle Animal works on Animal Companion all right, as explored in more detail here. But it uses does not include fooling animal. This skill is limited to:
- Handle an Animal - This task involves commanding an animal to perform a task or trick that it knows.
- To push an animal means to get it to perform a task or trick that it doesn’t know but is physically capable of performing.
- Teach an Animal a Trick
- Train an Animal for a Purpose
- Rear a Wild Animal
Nothing here about pretending to be an owner.
Bluff requires interaction. Faking master's voice can do the trick. Note, that:
Two circumstances can weigh against you: The bluff is hard to believe, or the action that the target is asked to take goes against its self-interest, nature, personality, orders, or the like.
Animal could get Sense Motive bonuses of +20 for too incredible to consider (wrong smell and clothes) +10 for putting it in danger, total +30 on top of its natural bonus. A bit too high to be reasonably considered.
Perfectly reasonable uses would be:
Feinting in Combat
You can also use Bluff to mislead an opponent in melee combat (so that it can’t dodge your next attack effectively). To feint, make a Bluff check opposed by your target’s Sense Motive check, but in this case, the target may add its base attack bonus to the roll along with any other applicable modifiers.
Creating a Diversion to Hide
You can use the Bluff skill to help you hide. A successful Bluff check gives you the momentary diversion you need to attempt a Hide check while people are aware of you. This usage does not provoke an attack of opportunity.
Disguise is the main skill for "I'm that man" type of play. Still, Animal companion would get Intimate +10 familiarity bonus to counter it.
How would I rule?
Successful Disguise check plus successful Handle Animal (push) check could work. "the animal performs the task or trick on its next action" part would give the Druid a chance to counter it before it happens, though. And said checks would be hard.
Successful Bluff could create confusion that would let you stab said animal more effectively, or hide yourself, but that would be the limit I would put, as this is both my understanding of the rules, and, in my experience, border of what my players would still find fun and interesting.