Do you mean only 1709 or also another years?
But could you point out situations when he neglected to keep his soldiers in a good shape? Didn't he care enough about maintenance, quarters, weapons for soldiers? Did he do for his soldiers less than any ther commander of that period?
It seems to me that your bad opinion about Karl XII comes only from one source - he subordinated Sweden and Swedish soldiers to his personal ambitions. He less cared about their subjects than about his personal priorities.
It means that he was better commander than politician

. You don't need to admire him as a politician, but I don't see a reason to underestimate his military achievements.
You know, Polish nobles were generally pacifists. Sweden gave back Prussian ports in 1635; Vistula trade was free from Swedish blockade. All of this without a single shot. The problem of Northern Livonia was postponed, but Poland didn't resign this land. The issue of rights of Polish king to Swedish throne was only king's problem. An average Polish nobleman didn't care about it at all.So nobles stated - it's enough for us by now; it's time to rest and rebuild our resources; we will come back to Livonian problem when the armistice is finished.
Remember that Poland waged constant wars from 1600 until 1634. It just finished 2 very expensive wars (vs Ottomans and Russians). There was really little enthusiasm for any new war, particulary against enemy who was so compliant like Sweden in 1635.
I think that Karl XII knew Polish realia much better. Sacking nobility and Sejm could finish only in one way - all the country and society must join to August vs Swedish barbarians. Karl X Gustav did similar mistake in 1655, when he permited to lay a siege to Jasna Góra monastry.
Karl XII didn't do what you would do. Therefore Poland neutralised itself in a civil war. Part of Poland wasted its resources and energy to fight another part of Poland. Nobility didn't have a clear situation - who was a true enemy.
IMO it was an excellent political decision of the Swedish king. Divide at impera
