“Can you try to be more specific when you say “include slavery”.”
Article I, Section 2. Start with that.
Assuming you are referencing clause 3, I shouldn’t have to explain the meaning of the word compromise to you. Let’s just say that your mythical 9 “northern slave states” compromised for the sake of forming a union with their southern counterparts by acknowledging the growing importance of Slaves and Slavery in the South. They very reluctantly made this compromise as is well documented and as you well know. The Declaration of Independence was the first move away from Britain and its foisting of slavery. You do know the North was moving away from slavery, while the South was doubling down on the peculiar institution. Has it occurred to you that if the Southern States were not so dependent on Slavery that the US Constitution might well have included an Emmancipation article? Slavery was on the way out in the North. How do the facts align with your gross statement that the nine northern slave states included slavery in the Constitution? Does it make it seem just a bit of a stretch to you (and your mouse)?