It depends on what you are doing in the script. Is it possible to share some examples?
Are you creating/destroying a lot of objects? You can get an easy performance boost by reusing objects instead of creating/destroying them.
You can look at the profiler results to narrow down the issue, debugHud->ToggleAll().
You can write Urho programs in C++, which can give a performance boost, although it's probably not as big of a boost as you might imagine because angelscript performs pretty well already. But for running on Raspberry Pi, maybe it will give a more noticeable improvement.
If you like working with Angelscript, you can move the slow parts to C++ and call it from Angelscript.