There are no 9 worst generation dudes able to fight Kaido
1. Zoros “cure” has a time limit
2. robin can barely stand after her fight
3. Sanji talking about the miracles about luffy winning and leave it up to him
4. zoro saying luffy will win
I can go on but there’s nothing indicating the straw hats will fight kaido. Take in account that luffy couldn’t even use his own power to defeat the thriller bark villians or even fight on par with them without the others giving him the shadows.
This luffy is able to fight on par with kaido and the 1v1 legend exists for a reason