VM with Virtual Harware version 9 and VMTools version 10.1.15.
Is there any sort of incompatiblity ?
VMtools doesn't usually have a dependency upon hardware version, so no, there should be no problem.
I hear that too, read this on some forum, but I didn't find anything "official" .
VMTools 10.1.15 aren't compatible with ESXi version lower than 5.5. Hardware Version 9 come with ESXi 5.1.
So still not sure...