I looked at the card for time and I doubt Okada is going to get his 6 star match with a 17 minute match. They are going to need an extra 25 minutes for the final 2 matches. So I see those 6 and 8 tag matches not getting much and that Suzuki knockout match not even getting close to 10 minutes.
If I had to venture a guess for match times, probably everything except the e main matches (Styles/Naito, Ibushi/Swagsuke, Tanahashi/Okada) will be 10-15 minutes or under with Anderson/Gallows vs. Goto/Shibata, Taguchi/Omega, and Makabe/Ishii probably getting around 15. I could see Styles/Naito and Ibushi/Swagsuke getting about 20 minutes each, while a full 30 gets devoted to Tanahasi/Okada.
So to work that out...
Jr. Tag Title 4-way - 10 min
Six Man - 10 min
8 man - 10 min
Sakuraba/Suzuki - 10 min
Ishii/Makabe - 15 min
Taguchi/Omega - 15 min
Tag title match - 15 min
Styles/Naito - 20 min
Nakamura/Ibushi - 20 min
Tanahashi/Okada - 30 min
That comes to about 2 and a half hours, with the extra hour and a half for entrances and whatnot. You could easily tack on another 5 minutes to a couple of the undercard matches.
Also, I know this is my second time asking (sorry) but I'm looking for somebody to help make some decent images showing the WK9 matches for the OT that I will be making on Dec. 28. If anyone can help me out please respond or PM me.