The problem with the OP is that the IJN will sit in the corner of the planning room wondering how they fight a decisive battle with a mixed force of 20-25 battleship from RN/USN when they only have 9.......
After the assassination of Tsuyoshi Inukai in May 1932, there's really no good option. It would almost be better to let the Army invade the Soviet Union and let them take the blame when they get defeated.
