I found this in a search: n cases where a candidate has only one name (Given Name or Surname), when provided with documentation, ISC2 can update your name to meet Pearson VUE requirements. "The Pearson VUE system requires a first and last name, so a period/full stop (.) or underscore (_) may appear in place of one of the names.
I would probably go to the Pearson Vue site and ask. It never hurts to be sure. Best wishes.