Bored with Bruno? Never!
The very thought. Pah!
With regard to the nose biting thing, believe it or not, it really is a sign of affection, albeit potentially unwelcome. You can, if you want to discourage him, move him firmly but gently away, while saying "No" or "Ouch" and turning your face away from him.
He's a bit young for bad breath due to dental disease, although it can sometimes indicate other problems too - more commonly in older cats it can be down to liver or kidney problems, or diabetes. In Bruno's case, I'm wondering if it's little more than some food which has got trapped in his teeth?
I know of people who do brush their cats teeth, and you can get cat dental brushes from Pets at Home - they're like little rubber thimbles which fit over your finger. I personally wouldnt rate my chances much of trying it with our two, but would be interested to learn how you got on if you try it.