If you want to level pets there's a fairly easy way to go about it. The Shadowmoon trainer associated with the Pet daily quests (A draenei child, can't remember her name) has some interesting, and exploitable, mechanics.
She has 2 actual pets that'll attack you and then a plushie that has no attacks.
The best way to do this is to bring 1/2 level 25 pets to deal with the proper battle pets, and then kill the plushie with the low level. The approximate EXP gain for that will net you 11 levels of EXP without ever having to fear that your low level pet will get K.O'd.
Not really helpful if you wanna get PvP done, but it's a quick and painless way to get your "low levels" to max faster