It has been sometime since I have salary sacrificed but when I did it was up to the company you worked for as to whether they paid the 9.5% on the sacrificed portion or not.
Many work sites that have EBA's generally had it in the section on Superannuation would have stipulation that the Company pays it.
I believe that it was changed from this year that they have to pay the Super Guarantee on the sacrificed portion too.
Google ATO Superannuation Salary Sacrifice or similar.
