I did this a lot this summer, as I had a community garden plot. I did two different things, as putting the poos directly on the plants won't burn them, but they don't really break down so well by themselves.
I made "poo tea" which was accomplished by soaking poo pellets in water in a pitcher for several days. This breaks the pellets down and you get a slushy, smelly, dark liquid that is GREAT for pouring on your plants to fertilize them. I separated the poos from the litter by putting a grid, called plastic canvas, over the pine pellets in the litterbox. My bunnies are also not very good about pooping in the pan, so daily I would go around and collect stray poops. It was a pre-bedtime ritual, and we called it being the poo fairy. LOL Silly and strange I know.
I also put used litter, poo, coffee grounds, hay, kitchen scraps (of the vegetable kind), etc in a worm bin on the porch. This was a big rubbermaid tub with a wire grid placed in the middle to divide it into two compartments. I bought a bunch of red worms at the bait store and put them in there. I'd put the fresher stuff on one side, and the idea is that once they worms are done eating up the stuff on one side, they go to the other, so you can harvest nice compost worm casings. I found that the urine-soaked sawdust didn't break down as quickly or smell-lessly as I'd like, so in the future I think I will only put hay, poo, coffee grounds, and veggie scraps in there. I think the pine litter contributed to killing my worms. If you have a more conventional compost pile, such as a large backyard tumbler, etc, I bet the litter would be fine. The way a worm bin works is different from a traditional compost pile--it relies on worms to break down the composted stuff. Traditional bins rely on heat and can get quite hot, which is why you can compost things that potentially contain harmful bacteria (such as egg shells) in them. Plus the rabbit urine is very basic, and I think the worms didn't like that.
Rabbit poo doesn't burn if applied directly, and it is 2.4% nitrogen, 1.4% phosphate, and 0.6% potash, for a NPK ratio of 2.4:1.4:0.6, which is very good.