Does anyone know if it is currently possible to customise the Office 365 calendar, so that it appears more user friendly for younger students, for example, it could show lessons instead of times?
No, it's not possible to customize the calendar. Sorry.
The work week view only have the time scale on the left - the times won't be in the appointments.
If you're running the latest version of Outlook/Office, you can request new features that you would like to see. Whilst Outlook is open, click File > Feedback > Outlook 2016 Feedback next to Suggest a feature.
It may get included if there are many upvotes. https://outlook.uservoice.com/forums/322590-outlook-2016-for-windows