In theory, yes, but WebAssembly current has put little effort on standardizing packaging and ABIs. That work is in progress here: https://github.com/WebAssembly/tool-conventions but is still very early. You'd then need each of these platform exposing a standard set of imports to WebAssembly binaries because from the compiler's perspective WebAssembly looks like an OS with a virtual ISA, so these embedder imports are kind of like an OS' syscalls. That's a lot of work, isn't very advanced yet, but in theory is all possible and WebAssembly was explicitly designed to make it possible.