I was really worried too when mine was spayed. I couldn't get her spayed until she was 7 months as she was still too tiny (my vets will only spay once they're above 2KG but not all vets do this) so my anxiety just built and built!
I took her in to the vets around 9am and they called me at 1pm to explain everything went well and I could collect her at 2pm. With regards to the worry for her opening her stiches I bought her a recovery suit so she didn't have to wear the cone. To save me having to put it on her and struggle, I asked the vets to do it while she was coming round off the anesthesia.
When we got her home she was very out of it (as expected) and she really struggled to walk in her recovery suit. I was debating on calling the vets about it until she decided she needed some water and managed to move about in her suit. I think she was really struggling to walk but also being a bit dramatic in the hopes I would take it off her! After a few hours she was moving about perfectly fine in it but was very tired and her pupils were dilated from the drugs. She was a little bit aggressive at times but again, due to the drugs she was struggling to make sense of anything!
I tried to keep her off the bed/off my lap so she wasn't jumping a lot but she ignored me and still jumped on my lap for cuddles. As long as you can keep the jumping to a minimum they will be ok. She had the recovery suit on for two weeks just to ensure it was all healed.
If you are at all worried about anything though, call your vet - even if it feels like you are being persistent and paranoid, it's better than worrying! I had Thursday - Sunday off when my cat was spayed and on the Monday my friend came to check on her and she was her usual self (running round the house like a crackhead)
Drop me a message if you want any advice :) x
If your cat is that distressed by it just get a baby shirt that covers the incision (check with your vet first).
There are even kitty versions...
He'll be able to groom more of himself but won't be able to get to his sutures.
I believe 1-3 month fits most cats.
Otherwise we'd just get a Comfy Cone and turn it down a bit. Most cats are a small. My tiny kitty is about the size of a typical 9 month old kitten, hers is an extra small but she can still fit her sisters size small cone.
In the evening we would do supervised cone free time. I know it's hard to watch your kitty feeling uncomfortable or in distress, but the sooner he heals the faster he's done with the cone. He'll be used to it to a certain extent soon.
Hope your kitty heals quickly!