Based on what, exactly? Would normal PS shit on Hachibi? Sure. Would Rikudo PS shit on Rikudo Hachibi?Sure, if they got the same boost, which is clearly not the case, as Kakashi's Rikudo chakra is almost negligible when compared to Bee's half of Rikudo's chakra. Not saying Bee wins here, but Kakashi beating him with PS alone is pure nonsense.
The gap between the weakest PS ever seen in this Manga by far (Sasuke's) and Hachibi is humongous first of all, let alone Madara's.
So Kakashi doesn't need an equal boost if he wants to shit on Hachibi. Not even close. Second of all the bold is literally based off of nothing considering the gap in power between Sasuke and Kakashi doesn't reflect "negligible" in any way, shape or form. Despite his chakra being less in quantity than Naruto and Sasuke's, his PS still shows speed feats close enough to their level where I can confidently say that Hachibi stands no chance. Not to mention Kakashi's PS has abilities outside of raw power. What you should be comparing is the strength of the chakra anyway, not the size of it. And yes, Hagoromo's chakra is >>Madara's when it comes to strength, but enough for me to say Hachibi takes out Kakashi? No.
Hachibi's Bijuu Dama would be only half of what Naruto can pull of at VoTE at the most. Please tell me how he's breaking through Perfect Susanoo with his Bijuu Dama when RSM Naruto wouldn't be able to fodderize Kakashi's Susanoo with a single Bijuu Dama. Even if you want to give Hachibi feats only Kurama has and say that he can supercharge his Bijuu Dama, Kamui Shuriken would still warp it away. Then PS hits him over and over again till he falls.
PS and it's weapons are all Kakashi needs to spank B here.