"Currently whenever I try to update the Safari version 8.0, it always shows the safari 10.0 version and above."
That's because that's all Apple is offering for Safari updates for your OS. There's only one way around it from Apple.
One of my setups is running 10.9 and that has version 9 of Safari on it, so if you install 10.9, you should get Safari 9 with it. My Safari is actually 9.1.3, but that's because it was updated once or twice since I installed 10.9. The only way you can get 10.9 is if you've downloaded it before, then check in your purchases, or if that's the OS your Mac shipped with from Apple. Otherwise, the only OS Apple offers is 10.12 Sierra, which is the current OS. That's just the way Apple does it.
Again, you cannot get just Safari, it comes with the OS.