Ciao Nicola,
Thanks for replying. I know that a notebook (.nb) can be saved as a CDF but I've checked the standard Mathematica install in raspbian stretch and it seems that it doesn't come with CDF Player. So I'm assuming that I will have to download the installer for the new Wolfram Engine in order to get the CDF Player, as you suggest. Which begs the question, does the Wolfram Engine installer cater to the ARM-based RPi or just x86/amd64 Linux installs? Also, do you know if the player can be called from within a wolframscript session a-la-Tkinter in Python? I haven't yet tried it myself as I don't have access to my RPi because of travel obligations. Grazie!