Instead you can get deterant sprays and stuff that could teach kitty to stay away from crib if you want to try.
You're not horrible. Did you adopt the cat before or after baby? I had a crib tent to try keeping the cats out. Eventually after the efforts to keep the cats out we decided to move baby to his own room and everyone actually slept better that way. Now his room door can be closed, cat free safe environment and our bedroom is where the cats usually spend a good portion of the day. They love sleeping with us. Obviously that's not an option for everyone. But you're totally not horrible for worrying about your babies safety. You can try the deterent spray outside your bedroom door and keep cat out of bedroom at night and hopefully the spray will keep him from scratching. Get him several cozy sleeping spots outside the bedroom and put some catnip on those. You may want to get your son allergy tested asap. At the end of the day, if none of this works I wouldn't blame you for having to return the cat. Especially if you haven't had the cat very long and your son is possibly allergic...
So my niece told me with her cat, she had to put a sheet over the top of the crib to keep her cat out
Buy a cheap crib or a 2nd hand one and have that for the cat. That will solve that problem. Use cat nip on it as-well. Also get a muslin cloth and get your babies scent on it and put it in there. You will no longer have no problems. Don’t use deterrent sprays on your babies crib it’s not good for the baby. Instead use Vicks vapor rub or use mint essential oil. (Not on the mattress).
It was just bad timing! New baby and new cat, who is older and gonna be a little harder to teach, is just a bit too much at once.