Thanks so much for your helpful reply.I apologize, I was off line when you replied last night.
When a normally sweet kitty becomes aggressive he is usually dealing with pain or discomfort. However, you say Rupert has always been a scratcher.
Feel all over his body and look in his mouth for a stuck item or any abnormalities.
If you do not find anything, Rupert may have a touch of kitty dementia.
Hyperthyroid is another disease of older cats that can cause aggression:
Of course, Rupert may just be getting a bit insecure and just wants your attention.
This is NOT a mean or aggressive cat. He just becomes overstimulated.
This is the way cats act when they play with other cats -they have a specific
language they use to communicate with each other.
The trick is to watch his body language and stop petting the instant you see
his tail swish or his ears go back.
I had a similar problem with one of mine.
I put a stop to it by teaching him he will NEVER get my attention if he uses
his teeth or claws. He can only get petting when he approaches me calmly and
NEVER SPRAY WATER! That is a definite NONO! It actually causes more aggression. Just say NO! and turn your back. You do not want to give any attention, even negative. Just ignore him. You can clap your hands or shake a can of coins.
When he comes to you quietly you must immediately give him a treat so he knows he did the right thing. Once he realizes he will only get attention when he is calm, he will change his behavior.
You can also get him a feliway collar or plug-in to keep him calm:
some of his behavior can be caused by boredom so put our foraging and interactive toys to appeal to his hunting instincts.
Rupert needs more exercise so play with him to tire him out.
Please let me know how things go. If you still have questions just press reply and I will always be here for you.
Warmest best wishes,