#7 is chiefly BE. I could guess it from the context, I suppose, but if you want to be sure that AE speakers would understand it as well, I'd use one of the other suggestions here.
Wirklich mit me?
Der Angesprochene soll nicht mir die zehn Minuten ersparen, sondern sie für mich aufwenden ... (for a chat with me).
As others have pointed out, "spare me some time" is correct. In this case, "spare" is used in the sense of "give":
spare verb (GIVE)
to give time or money to someone:
I have to go soon, but I can spare a few minutes.
[ + two objects ] Can you spare me some change?
I'd say that it also works without the "me," though.