He may have pain as a result of his declawing. I know you cannot go back in time and undo that decision now, but I would recommend against it in the future. Has he been to the vet to check and see if he's in pain somehow? That can cause changes in behavior.

I know you love him, how do you react when he misbehaves now? Have you tried spritzing him with water when he does that? Is there any way you could just, for example, shut him in the bedroom when company is coming over? He may just view visitors as stress, and is acting out.

First and foremost, I'd get him checked by the vet, to make certain there's no sudden underlying medical reason for his change in behavior. I know I get cranky when I'm in pain ...

Once you have ruled that out, then you can work on behavior modification.