a-Shell [1][2] has WebAssembly (and WASI) support and ships with a compiler that compiles to, you guessed it, Wasm. Though there are limitations on what can be done, such as no sockets, no forks, and etc...
around 2020 Apples iOS added technical support for JIT, but the chances that your app gets approved are slim
you can AOT wasm to a normal dynamic library and ship that
various wasm runtimes support an interpreter mode, this slow but might still be fast enough
JavaScripCore supports WASM so you can make apple run the WASM for you ... but more or less in a browser sandbox.
The app store still has rules forbidding any form of dynamic execution of code which wasn't either shipped with the app or typed by the user independent of technical solution.