\def\myfootnotecommand#1{\hbox to 1.5em{#1.}}
</texcode>
* Can I change the line spacing of a footnote independently of that of the main text?
The way to do this is not obvious, but this is the code you need to use:
<texcode>
\def\setnotebodyfont
{\switchtobodyfont[9pt]\setupinterlinespace[your desired spacing]}
</texcode>