Question about the next LTS

So, I'm new to the Zorin OS, and have purchased the zorin 10 ultimate a while ago, and as it only has support for some months, will a new LTS come after zorin os 10 ends or after Zorin 9 ends?

Well its hard to say - a lot will depend on how Ubuntu (Canonical) are going to play it. 12.04 (Zorin 6) was to be supported until April 2017, which is still the case but security issues came to light that glibc means that it may not be worth continuing with 12.04. Then Ubuntu came out with 14.04 (Zorin 9) also a 5 year support release 'til 2019 - so if this is a pattern that Ubuntu is following the next LTS may well be in 16.04? Zorin 11? Whilst Ubuntu comes out with new releases every 6 months, Zorin will come out with the most stable release - I think they came out with 8 based on 13.04 (or 13.10 - I can't remember) but each intermediate release is a 'development' release. To upgrade you would need to follow Wolfman's upgrade guide in the Post installation guide here:

viewtopic.php?f=3&t=2054

So, should I just get Zorin 9? What happens when support for Zorin 10 ends? Will Zorin 11 come out?

Just from the point of view of Long Term Support with the least number of potential headaches I would stay with 9. I have no idea what the brothers Zorin have in mind for when Zorin 11 comes out or what version of Ubuntu it will be based on.