The answer is all the patch 2.0 changes will go live. Things that you do have access to without RotHC like new talent trees will be available to you. However, Makeb and all it's features like getting to 55 will not be accessible until you purchase RotHC and wait for it's launch on the 14th.
Hope this helps clarify it for you.
Based on that, help me to clarify this, after the deployment of the patch on the 9th I'm not eligible to early access will I be able to gain XP on my level 50 toons?