@Anthony ******
Here's my advice:
1. If you're going to be a consultant in Thailand, you'll need a work permit and a Non-B visa. I'm assuming you'll work "under the table".
2. There are no "9 month visa". The visas that will allow you to stay 9 months are a METV, or multiple entry Non-O. There may be some other types of visas as well.
3. If you arrive in Thailand on a visa exemption, you will (probably) be staying here on visa exempts, visa extensions, and tourist visas in Laos/ Malaysia. You *MAY* be able to get 9 months doing that here.