The -O flag is used to pass alias names, not options. So one choice is to create an alias:
:aliases {:xb {:jvm-opts ["–add-modules java.xml.bind"]}}
then activate the alias at the command line:
clj -O:xb ...etc...
Or you can supply jvm options directly in the command line with -J:
clj -J–add-modules java.xml.bind ...etc...