I want to know which version is more optimized and stable from 4.0.2 - 4.9.1 I don’t mind not having all the latest and new features present as long as it is optimized and stable when building a game.
When you start using 4.9, until your game is finished there will be 2 or 3 new versions of UE4. Just use the latest one
You should absolutely use the latest version of the engine, though you may not want to switch/update during mid-development due to changes in each version. Each new version of UE4 has SUBSTANTIAL improvements, you’ll want to start off with 4.9 .
I personally would also go with 4.9 as you have some new features + bug fixes 
But just update the engine when it’s a “final” release and not just a preview
I agree with and =)
PS:Excuse me. I don’t know english very well=)
Thanks Guys!!! I"ll be on 4.9.2. Does anyone know why Animation Starter Pack is still not compatible with the latest version?
It is up to the content creators to verify that their content is compatible with the latest versions of the engine. They have 10 days after a major update to update their content or notify Epic that it may take them a little longer, or their content may be removed from the marketplace.
Here you can read more about the “marketplace updating topic” -> https://forums.unrealengine/showthread.php?85688-Why-is-most-of-the-stuff-in-the-marketplace-not-compatible-with-unreal-engine-4-9 
It’s my experience that that’s usually short-sighted. It’s often prudent to not upgrade to the “.0” version when you’re already making a project, but once “.1” rolls around of the new version, it’s time to update. If you don’t, you will run into known bugs, and you won’t be able to fix them because they’re already fixed in newer versions. And, finally, you’ll realize you HAVE to update – two days before hard freeze. Better pay it at a time you can control, and not have to worry about those bugs at all during development.
29 times out of 30, a content pack will work just fine with a newer version of the engine.
To add it to a project, click “add to project,” then in the add dialog box, check the “show all projects” checkbox, choose your (newer) project, and then select the latest available version number to actually add.
Once it’s added, open it up in the engine, and it should work fine.
Once in a blue moon, some required blueprint functions have changed, and you’ll have to re-wire some missing nodes. This is similar to the kinds of things that CAN happen when upgrading project between versions. As long as you’re methodical about it, it’s really quite easy, and well worth the effort.
Thank you for all the response. The Animation Starter Pack just became compatible to 4.9 version. Hopefully other assets will be soon too.