Luig was also nutered when he was 6 monthes and he didi great!!!! When the dr. called me to tell me how he did, I was able to hear him in the back ground and he was as feisty as ever. She couldn't believe how percky he was. He too had teeth pulled-9 to be exact!!- and was microchpped too. He did sleep the rest of the night when we got home til morning, then he awoke and was back to normal!! I don't think it even fazed him. I couldn't keep him from jumping and stuff. But my vet also did some blood work and some other tests before surgery to make sure all his "stuff" was normal!!!!
I was nervous too but trust your vet- he will be fine!!!