How Many Seasons Are There of How I Met Your Mother?

I usually keep pretty good track of my favorite shows. I know how many seasons there are as well as how many I've watched. I was watching How I Met Your Mother on Netflix and I was pretty sure that there were nine seasons. However, at the end of the 8th season I started panicking and wondering if I had this fact all wrong. Maybe I only had two or three episodes left and this sent me into panic mode. I decided to ration them carefully. Then I looked it up and there are nine seasons even though it seems like it could’ve ended at eight.