Although the colors have probably been juiced to some extent, the 9.4 is also in the newer slab. The newer slab presents a book's actual colors more accurately and favorably than the older slab.
First time I've heard of this, but you may be right. I do prefer the newer slabs, much more superior and sturdier, also the CGC label colors and texts are bolder and sharper compared to the previous labels making it easier to read from afar. But, I highly doubt even in the newer slab, the Bats 1 9.4 does not have those kinds of colors going for it in person. Of course I could be wrong because I have not seen the book in person. There are have been numerous known instances where HA does brighten up the scans of their books to possibly boost up the bidding activity realizing a higher hammer price. So, I will stick to the the buyer's first-hand accounts.