Duncan_Randar
After the Greyjoy rebellion he will have 9 years to prepare for the 5 kings war. He already has some idea of how he's going to develop his house because it's time for some of those critical war items like gunpowder, to destroy walls and gates, not yet using it on ships because it would change naval wars a lot, and uses Greek fire on ships and it strengthens the cavalry because it makes things so much easier.
His family has already done enough in this war killing the Drumms and destroying 100 ships, so he doesn't lose any more men, make him ask to be in charge of the invasion of old wyk the island of Drumm's house so it will be easier since they they've already lost the ability to defend themselves and they haven't had to sacrifice many of their men, and when king robert leaves Balon Greyjoy alive he can ask the king to do something like the treaty of versailles, making the families of the iron islands pay an exorbitant sum of money and limiting the greyjoy's land and mainly naval power thus breaking them and greatly impeding their development.