I think we might actually need TWO wins to make the tournament, not one.
The reason: if we win one more game, it is very likely that we are playing in the play in round. Big Ten tiebreakers start with head to head first and if multiple teams are involved, record against all teams that are tied comes into play.
Their are five teams that realistically could finish with 9 wins (I'm not counting Michigan, who has 9 wins already and plays Nebraska at home among their last three games). IF Purdue and Indiana end with 9 wins, that kills IU in tiebreakers with not just Purdue but with any other team with 9 wins. Purdue plays at Iowa and then hosts Rutgers. The best case for IU would be for Purdue to lose both; the worst case isn't really Purdue winning both, it would be them splitting the pair because it would push IU below some teams they might otherwise beat in a tiebreaker.
So if IU finishes 9-11 in conference, they very likely have to play Wednesday in the BTT against either Northwestern or Nebraska. While 19-12/9-11 puts them on the right side of a bubble, a BTT ending loss to Northwestern or Nebraska brings in a bad loss and hurts the resume. So I think we need two wins....either during the regular season, or if we get only one, we probably need to either beat Nebraska or Northwestern in the BTT.