That is such an awesome way to break it down thank you so much! I think what is throwing me off is that I have to relate it to the curriculum. For example if I did the tennis ball example and how they bounce and the different types of rubber and such I would have no idea how to relate that back to the curriculum. Like you said I could discuss the chemical structures of the rubber and its impact on material properties... but in grade 12 we look at structures and properties at the quantum level.
Well, in your opening post you mention organic chemistry as part of the curriculum. There's a lot of organic chemistry in manufacturing polymers. I am not sure exactly what is meant by "at the quantum level". (I mean, you said there's someone doing a food topic - and I think food is a great way to go; everyone loves food - how is quantum chemistry being related to food? Ultimately all bonding is derived from quantum mechanical principles, but we don't necessarily need to invoke those principles specifically to understand macroscale chemistry.)
Here are some topics that interest me (generally and what may have some chemistry to it)... Dance, psychology, music, medicine and its affect on the body, how bleach makes hair lighter, why sulphate free shampoos and conditioners are better for your hair, energy drinks, lava lamps, bass and its effect on sound when listening to music, shellac nails and why acetone is the only way to remove it, lulu lemon legging material. Random I know but anyway these topics could be related to things within the curriculum?
Dance and music are probably more related to physics than chemistry. But any kind of physical activity has chemical effects on the body. Related biochemical topics could include endorphins, lactate production, cellular respiration, the chemistry behind how muscles work (that's a great topic actually: myosins, myoglobin, etc; lot of physical chemistry there). A talk that focuses on the chemistry but relates it to something you enjoy (like dance) would be engaging.
Medicine - that's almost too broad a topic. What aspects of it are you interested in? Is there a specific disease that's important/personal to you? You could focus on the biochemical mechanism of pathology and the chemistry behind any modern pharmaceutical treatments.
Hair dye is an interesting one. What pigments are responsible for hair color, and why does a bleach work? There's a lot of quantum topics you could touch on related to pigmentation and light absorption.
Sulfates in shampoos and conditioners... not sure about that one specifically, but you could certainly broaden it to talk about general ingredients in shampoos and conditioners. Surfactants are a great topic for a chemistry presentation, and have a lot to do with kinetics, surface energy, organic chemistry, and so forth.
Energy drinks. The first thing that comes to mind is caffeine. Obvious ways you could go with that one.
Music, I'm not sure how that would relate to chemistry, honestly.
Shellac nails - I don't know if there's enough meat there for a whole presentation.
Lulu lemon legging material... haha, what is that? Anyway, textiles are basically polymers. There's a lot of ways you could go with that topic. Not sure what they are made of, but let's pretend they were made of spandex. Spandex is a copolymer designed to have extremely elastic properties... kind of like a rubber. There's a lot of materials chemistry you could go into, in fact very relatable to tennis balls.
I could easily see an interesting presentation on different types of fabrics, what kind of synthetic and natural polymers they are made of, and how that translates into function. Why are cottons "breatheable"? Why does spandex stretch? Why are nylons made of... nylon? Ultimately it all boils down to chemical structure of the polymers they are made with.
Hope that stoked your imagination! The important thing will be to pick a topic. Any topic in chemistry can somehow be related to physical chemistry principles: energy, bonding, kinetics. You can figure out those relations later, but first pick a topic that has potential and is interesting to you. I think a lot of the ones you mentioned could be used.