Can you take the baby rabbit out at 8 days old?

No, 8 weeks is too young to spay a rabbit because she isn't sexually mature yet. Female rabbits can be spayed as young as 4 months, but surgery is risky on such a young rabbit so most vets prefer to wait until about 6 months before spaying a rabbit.

Male rabbits can be neutered once their testicles descend, usually around 4 months. The neuter surgery is much less invasive than the spay surgery.