found time to re-install VBR 9.x and re-create Media Pools again. See the results here ...
Look on the left side and look on the right side. On the left side sorting is wrong, on the right side it is correct. This doesn't happen with all names, but with these names and the original names, which you don't see here, but it is an evidence that name sorting is incorrect and not only with our original Media Pool names.
Restarting VBR is necessary.
Please fix this asap, as this is really annoying.