Hi Tony,
You can go ahead and just install ROM version #10 as version #10 incorporates all the changes in #7, 8, & 9.
The fixes in ROM version #10 address software issues related to lyrics display and associated keysoftservice software "HD-Techmanger". Other fixes include "improved" OS software efficiency but you probably won't notice the difference.
If you do not have the HD-AE5000 hard drive installed in your KN5000 it is not essential to update to ROM #10 from ROM version #6, nonetheless updating your ROM to Version #10 is very safe and easy.
Regards,
- Scott