Well, IU has its own plane, right? So, it can go whenever it wants.
But the game won't be over until about 11:30 p.m., and another hour will be spent at the Dayton Arena doing press conferences, showers, postgame taping/treatments etc. and then traveling for a half hour or so to the Dayton airport. That means takeoff/departure wouldn't be earlier than about 1 a.m. Wednesday.
Flying back (or busriding) to Bloomington would take at least another hour and maybe another separate bus ride to Assembly Hall before sending the team off to their local apartments around 2:30 or 3 a.m. at the earliest on Wednesday morning.
Then, under that scenario, the coaches will have to herd the team together on Wednesday midday to have another busride to the Bloomington airport, then a four hour flight to Portland and then another bus ride to the hotel.
I'm just assuming IU won't want to mess with all that and will just fly to Portland directly from Dayton and then let the team sleep in a bit and take advantage of the three-hour time difference for walkthroughs, team meetings, treatments, etc. in Portland later on Wednesday.
I may be wrong but it's a long sleepy trip either way. It's easier when you're 19.