The ninth place song needs a higher percentage of the overall vote than 11OTT's 42.55%. At the moment, the three songs tied for seventh to ninth (RTSS, OTH, Heartland) fall just short with 41.67%.
Hmm, that seems to be raising the bar even higher in favor of 11OTT. It's unbalanced enough in the first place to ask a 9th place song to compete with a 5th place song. But percentage just seems to throw any fairness out the window when you consider the wealth of beloved songs from this era.
I think total votes is a much more even comparison. Much more straightforward.
(Though if you're trying to compare 2 songs that weren't in the same poll, the only real fair way to do it would be to have a head-to-head tiebreaker.)