I don't think they are disrespectful, lazy or that staying in bed for some extra sleep is a waste of time as a teenager whose circadian rhythms have been completley disregarded in the planning of the school timetable. After significant research has been presented to document this, if anyone is being disrespectful and downright negligent, it's schools who continue to insist on a start time that has been proved to be detrimental to the health and wellbeing of teenagers.
As an adult I've had some of my best and most successful ideas lying in bed in those enormously fertile moments of peaceful, semi-dreamy enlightenment. Ideas that have gone on to be creative projects that have been commercially and critically successful. I could have been rushing myself up and out to attend an irrelevant meeting instead and would have lost out on all of that. For what? To please someone who likes rules for rules sake and forcing irrelevant meetings on people? It took me much longer to figure out than this excellent young person. They really are destined to go far.
Choosing to stay in bed rather than attend a meeting where you are expected, is nothing but disrespectful. It is saying you think your time is more important than those running the meeting/form/assembly. Again, not a good quality.
You say 'agree to disagree' but then present opinion as fact. This is not fact. I have already stated my opinion, I think this shows enormous intelligence, vision and creative thinking, good time management and self knowledge. Seeing these qualities infront of me I am excited by this young person's potential, not foaming at the mouth and crying 'disrespectful!'. In my many years of teaching and supporting young people I don't think I ever experienced disrespectful behaviour. Curiosity, vision, creativity, new ways of looking and thinking and, of course, plenty of boundary pushing, which is exactly what healthy, developing teens should be doing.
I also met many fabulous educators who harnessed these qualities, encouraged and supported young people to become independent learners and thinkers. But amongst us were also alway a handful of educators who were quick to criticise, moan about and seemingly actively dislike young people. The type who are quick to shout about 'disrespectful behaviour '. I could never fathom why they were in the job. They lacked the creativity, curiosity and vision of the young people they were there to guide and seemed terribly bitter about that. Once a person is in the right place they stop criticising others like this. Some don't achieve it in a lifetime, other know from the start. We can all find that place though, but it's rarely in an 8.30 meeting about something that bears no relevance to our interests.
Postscript
Spending time trying to beat the system just makes you look like a bit of a dick tbh.*
*See: Nelson Mandela, Ghandi, Martin Luther King, Martin Luther King Jr, Emmeline Pankhurst, Christine de Pizan, the women of the Rosemstrasse protest, Oscar Schindler, Muhammed Ali, Rosa Parks, Harvey Milk, Greta Thunberg, Malala Yousafazi...I mean the list goes on and on of these 'dicks' who tried to beat the system, doesn't it?