Seriously no matter who the Big 9 realistically want to add, if OK and Texas want to stay together and be part of a stable, financially successful, high profile conference, the answer is obvious.
The clock is ticking because if a school is actually invited into the Big 9, that implies OK and Texas have decided they want to stay in the Big 9.
Oklahoma deciding on options
Option 1:
OK, OSU, Texas, TT join Pac 16:
likely division: includes Arizona, ASU, Colorado, Utah
great regional mix plus tier one conference playoff game comparable to Big 10 and SEC.
Option 2:
OK, OSU, Texas, TT stay in Big 9 plus:
other teams: the "outsiders": include Baylor, Missouri, Kansas, KSU, ISU and whoever;
what potential big time team can anchor the "outsider" part of the conference to expand to 12?
what teams among the 5 "outsiders" and potential additional teams are so compelling that Texas and OK prefer them to the PAC 16 option.
From a geography, market, fan, academic, stability perspective: what are Texas and OK thinking?
A&M to the SEC makes this an easy decision.
Assumptions:
Texas and OK want to be together; Texas and OK want regional partner schools OSU, TT; Texas doesn't want to join the SEC; the PAC 16 is more attractive than the Big 10 from an affinity perspective to Texas and OK and partner schools; the Big 10 doesn't want TT or OSU regardless;