Nystul's Magic Aura to change a creature type to "humaniod".
Magic Jar to take control of it's body.
Possibly a Hold Person or Suggestion in the middle to make it go along with your plan.
Definitely takes some setup.
So running some quick math, the kraken is gonna succeed on its saves more often than not. At 11th level a wizard will have only gotten two ASIs, assuming they used both of them to boost an ability score instead of taking a feet, and chose Intelligence to boost that's a total of +4 to the asi. Let's look at the absolute minimum their intelligence might be first, then take a look at the maximum. For a primary ability you never want to start with anything less than a +2 mod, so those ASIs will get you up to a +4 for a spell save DC of 16, meaning the kraken only needs to roll an 11 for its save against magic jar and a 12 for its save against hold person or suggestion. And it only needs to make its save against the hold person to completely ruin the setup you did and at best force you back into your body and at worst instantly kill you by breaking the magic jar on its turn.
Absolute maximum for your primary ability score would be a 20 at first level if you got insanely lucky with rolled abilities, that only bumps our numbers up by 1, still pretty easy rolls for the kraken to make with how high its ability mods are. So let's see if we can swing our odds with any spells, abilities or feats. A quick search of the 2024 phb for the term disadvantage doesn't show much of anything that imposes disadvantage on saves but lets look at the few things that do:
Bestow Curse, well this requires a save to take effect in the first place so it suffers from the same issue as the other spells, and even then can only force disadvantage in whatever control spell you use to make the rest of this possible.
Contagion, mostly the same as bestow curse, it can impose disadvanage on saves but only if they fail a save first, this time con which the kraken has a +7 on. Granted if you succeed it has disadvantage for as long as it remains poisoned, so if you get lucky on your first turn you do improve your odds a little.
If we dip over to 2014 and bring over the div wizard subclass we can possibly force a failure on 2 saves, but only if you rolled less than a 12 for at least one of your portent dice and less than a 13 for the other, most likely this will only let you force one save at which point your back to the original odds