Yes, sam can be used on the command line with ssam [1]. It's specific to plan9port [2]. In the original Plan 9, ssam wasn't included because Rob Pike didn't want to give up the X command that handles multiple files [3]:

    I find the X command extremely powerful, and can't see any way to
    have a streaming implementation that will look at multiple files
    simultaneously.

> Is there a port to Apple silicon?

plan9port works on it. It compiled without any errors on my Apple Silicon Mac.

[1]: https://9fans.github.io/plan9port/man/man1/ssam.html

[2]: https://9fans.github.io/plan9port

[3]: https://9fans.topicbox.com/groups/9fans/Tdf6095a105816f01-M3...