I don't use Skype much but it is a nice back-up communication method and most people I know do use it, which makes it important. I love the system integration for Skype on my N9, still my primary phone, and it would bother me to have something visible in the beautiful system be broken. It would mar the perfection that is N9. But, I'm optimistic that it will continue to work past Oct 2016. One reason is that N9 is essentially Linux, and MS is actively developing support for Linux:
http://blogs.skype.com/2016/07/13/sk...d-chromebooks/

And the reason for Linux support is the China market. It is a critical market due to its sheer size. Looking at Warehouse downloads, the Chinese market is a huge chunk of Jolla/Harmattan users. These are also users who are very open to trying new things, obviously, and would readily switch to Skype alternatives, as opposed to Windows Phone and Blackberry users who are more likely to simply upgrade to Androids or iOS. (Or Windows 10 phone which should work -- MS now gives the same OS name for both the phone and desktop.)

The support is for a newly developed Linux client, but it may be an advantage that N9 Skype is fairly basic (no video for example) so perhaps there is nothing to break, at least unintentionally, and at least for now. So I don't think we'll be purposely killed. But Skype is "migrating to the cloud" according to the announcement and there is a fundamental difference in how new clients will operate. So I guess it depends on how Skype had been implemented on the N9, and whether any fixes will be possible.

Edit: Upon exploring the Skype web site some more, it seems the completion of migrating from a peer-to-peer use of Skype to being entirely cloud based is planned for "early 2017." (I also use a no-longer-supported MacOS, Snow Leopard, as my main Mac OS, which will still work until then even though "support" is dropped earlier. So, the client is no longer updated but peer-to-peer is not yet broken -- until "early 2017.")