It has been said that you can't PRE-ORDER with Cartel Coins. Unless something has been added in the last 18 hours, no mention of whether or not it would be available after it launches.
To answer the question posed here about purchasing Rise of the Hutt Cartel:
We'd like to clarify that Rise of the Hutt Cartel will be available for purchase through SWTOR.com/buy only, and there won't be an option to purchase it using Cartel Coins.
Please look before you speak. This ground has been covered...a few times.