No worries.
It just looks like the inner link is (or was) 'riding high'. on the teeth. Or at least that's what the mark shows (could be just 'gunk' from the inside of the chain).
Regarding the wear on the 'valley' of the cogs, wonder if it is caused by the lack of beveling on the inner side of the inner link on the 9 speed chain.
Here's a pic of a KMC 11 speed chain, don't know is Shimano's are the same.
