I agree with verifying that someone will be there overnight with him. Most do not have someone there. I brought Lulu home with me the same night as her surgery (Tuesday). Usually they keep the babies overnight, but since Lulu was so small & I requested to bring her home they allowed me to do so. They did keep her all day until closing time, though. But that was okay with me b/c she was getting IV fluids the whole time & was resting.
Good luck! I know it's stressful. I am beyond relieved that Lulu's spay is over with.