Hi Heidizie,
A phone call to the manufacturer is usually the best source of information about their mattresses but I can tell you that the Total Latex mattress has 6" of 36 ILD Talalay latex for the core (or you can choose 32 ILD or Dunlop as well) and then a 3" talalay latex comfort layer where you can choose the firmness level. The extra inch is the cover which is quilted with wool and a thin layer of polyfoam.
I would talk with them about your comfort choice and which may be best for you (the manufacturers themselves are always the best source of guidance for helping you to make the best choice for your body type and sleeping style). 9" of latex would be suitable for your weight and you certainly wouldn’t be bottoming out but some people that are a higher weight may prefer a thicker mattress because it has a greater range of compression and can be more adaptable with higher weights and different sleeping positions. You can read more about some of the potential benefits of a thicker mattress in post #14 here. The best way to know your preferences is if you are able to test various versions of latex mattresses locally to get a sense of what may work best for you.
You will likely need a firmer base layer (either the 36 ILD talalay or the Dunlop (you would need to ask them about its firmness level) and you would probably do best with firmer comfort layers as well (firmer foam feels softer with higher weights because you will sink in more that someone who is lighter).
Phoenix