Board Thread:The Reference Desk/@comment-26975268-20130223231514/@comment-4189499-20130224003708

Well, there is a little thing called retcon which could introduce a meeting between 9 and the cybermen in spin-off media and just ignore that one line in the TV show, or just set it before Rose came. We don't know exactly when 8 regenerated into 9, so maybe they met sometime during the Time War? But based on TV alone, it does seem that they haven't met before, but someone with a greater knowledge of the novels etc. should go check.