I agree with the premise, but that premise also applies to RBs. People are acting as though the team will only have one single opportunity to address RB in the off-season other than the #9 pick in this draft.
If you think Jeanty is a generational back, I get why you think he is a no brainer pick at #9.
But if you think he's just the best RB in this draft but not a generational talent, then there is room for debate whether that is worth the #9 pick. I think he's a very good back, but I'm not convinced that he is a generational back based on what I have seen and I think there are a lot of RBs in this draft that could come close to his level of production. If I am right in my evaluation of him, and I admittedly could be wrong, then he might not be the BPA at #9 and, if he is BPA he likely wouldn't be the best value at #9.
If he's not a generational RB, then I think you get more value by trading down, getting some more draft pick and a player lower in the draft because there will be other backs available later in the draft that could come close to, or even match his production. If you can't trade down, and he is BPA, I guess you have to take him, but that would not be the best scenario for this team.
You finally get a top 10 draft pick and you have to use it on a position that you can get similar production from late in the 1st, the 2nd round, or even 3rd round. I just can't get out of my head that 3 of the top 5 RBs in the NFL, maybe more after that, were not drafted in the 1st round and one of those that was drafted in the 1st round, isn't playing for the team that drafted them. And, the guy that might be the best RB to ever play for the Saints, a guy that Jeanty might not even be better than, was drafted in the 3rd round.