I've got Komplete 9 installed, which has Kontakt 5 in it. In SONAR, Kontakt doesn't show up in the insert synth menu (you know, that super long menu that only scrolls one-by-one). But when I use SONAR's browser set to instruments, Kontakt 5 shows up with a "32-bit" addendum. If I drag that into SONAR it loads up just fine. Since the other Komplete apps show up just fine I'm just wondering if I need to reinstall Kontakt, if there even is a 64-bit version. I've re-scanned my VSTs a few times now (and hey, spring cleaning!) and the results are the same.
 

I'd first make sure the Kontakt DLLs were installed to the correct folders for your configuration.   It definitely is or should be 64bit, and by default should give you three entries representing different output variations (8, 16 and 64 I think).
 

As stevec said: 3 entries. You may have unchecked the 64bit version during install (if that even is an option). Have you tried the latest update? Have you checked that the dlls are in a folder that Sonar scans for plugins? Else reinstall (you don't need to reinstall you libraries).

Hrm, yah missing .dll's. I just went ahead and reinstalled Komplete (just the instruments, not the sound banks) and am updating them all now. Thanks for the tip!