I have Cubase LE9.
I looked at the software specs and I saw that Cubase le9 have 16 instruments tracks. But I get only 8. Why?
Cubase LE has only 8 instrument tracks:
It’s Cubase AI (the one that’s included with Yamaha hardware) that has 16 instrument tracks.
It’s a good idea to upgrade to Cubase Elements if you need more. This will add a bunch of useful stuff for cheap, on top of upgrading you to 9.5, which has much better automation handling.