LBJ10 makes a really good point, there is a big difference between “bad” behavior and simply unsavory aspects of typical bunny behavior. My little girl is about 8 months old or so and I can give you a laundry list of “bad” behaviors that have subsided or stopped entirely since she’s been spayed. Peeing/pooping outside the box, aggression, lunging, nipping, making messes on the bed, circling ect. She’s also far more cuddly and friendly now – hopping up in bed with me every morning to cuddle and flopping against me (or even on top of me sometimes) for a nice long nap. She’s also much more communicative about when she wants to be petted without resorting to biting or scratching like she used to. That being said, she still chews on everything she can find because chewing is simply a bunny thing, not a hormonal thing that can be changed. Also, like the others said, girl bunnies have an extremely high rate of cancer by the age of 3 or 4 so it is vital that they get fixed. So yes, spaying and neutering is very important, even for a single child bunny.
The expression “f-ing like rabbits” was coined for a very good reason. “Mating season” is constant – 24/7, 365. She’s circling because she’s hormonal and sexually frustrated. She wants a boy bunny and she wants him now.
Your bunny will lead a much happier and healthier life if she is fixed. I imagine it’s quite frustrating to be so hormonal with absolutely no outlet for your entire life (at least boy bunnies can take it out on a couch cushion or something). She’s like a little nympho nun…