For Lisp variants ask Alex Shinn(alexsh...@gmail.com), he's got an interesting scheme implementation mostly working. It's a summer of code project this year.
Indeed, there are a number of fairly portable Scheme implementations that I could see working with Plan 9.
Aaron W. Hsu --Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. -- C. S. Lewis