Well, I might be misunderstanding or, perhaps, there might be a terminology problem here... him flying around in the same room you are is not 'one-on-one', it's 'out-of-cage' time. One-on-one implies you spending time with the bird and doing nothing else for a couple of hours. But, because some parrots can be happy just chilling with us, this one-on-one doesn't necessarily have to mean playing or training, it could be the bird sitting on your shoulder and cuddling or it could mean him sitting on your shoulder while you do chores (they love to 'supervise' us
). Senegals (all parrots, actually) love spending time with their owners and that means being on your shoulder. It's really hard with the large ones so some people just walk around with the bird perching on their arm but senegals are not satisfied with this, they want shoulder time so I think the problem with yours is that he is no longer a baby and is now beginning to assert himself firmly as to what he wants.
Yours is at the age when the problems begin. They are no longer babies that put up with anything without complaining much, they are now teenagers and they rebel just like human teenagers do. I would be very careful about not covering his cage at night if there is any light at all reaching his cage as well as not keeping him to a strict solar schedule because I've had many different species of parrots that came to me with aggression issues, from little ones to macaws, and the worst one BY FAR was a male Senegal (I still have him but he is fine now). This is the ONLY bird I have clipped in my life (something I regretted immediately after doing it) and it was done out of sheer desperation because I dreaded going into the birdroom with him attacking me relentlessly all the time that I was in there.
Senegals are not easy birds... they might be small but they are fearless and very stubborn, and can get terribly aggressive when overly hormonal so I suggest you start spending a good two hours a day with him (cuddling, scritching, playing, etc), keep him at a strict solar schedule with full exposure to dawn and dusk for, at least, 1.5 hours and stop free-feeding protein food.
Also, from my personal experience with them, they only chew when they are hormonal so I doubt that getting more chewing toys will help with the biting but, of course, it can't hurt either.