[andor]

You should take a look at info-beamer. It supports displaying video via FFMPEG, you could show browser content via VNC, and the best thing is that you can hot-swap the animation code while it is running. It's a bit like Processing, but much more lightweight.

Out of the box it doesn't solve your array problem, but maybe you can hack something up. For example, you could have a huge virtual display on your control laptop, and show parts of it on the Raspberry Pi's via VNC. Or you could have a "crop" parameter in all your animations, so that every Pi can render a different part (required perfect timing, though).

http://info-beamer.org/

[MalphasWats]

This looks interesting, thanks.

At the moment I don't want to use it as a single display, rather display 9 different things (and various permutations thereof).

I plan to hack something together, but I'm struggling to envision how it should all look, so this is a good start.