do you include name, address, school, GCSE subjects (school only offers double science) School awards, music grades, hobbies?
I'd omit music grades for irrelevance, but yes to the rest. Also a short profile upfront saying something like "Highly motivated GCSE (?) student seeking science-focused work placement to gain experience of the working world", or somesuch. Profiles are a very good, easy way to frame oneself to the reader, and they are underused imo.
You can also include the name, number and email addy of one referee if you like - the head of year or similar? Or "Reference available on request" at the bottom of the page.
If he has done any science projects, mention these in their own section ("Relevant experience").
No need to include DOB, passport numbers, a photo, availability on particular dates... People put all sorts of odd things in there.