I guess you can get adopted by one of the family owned demo companies, or you can get your training in the military. Trial and error could be fun, but you might have difficulty getting insurance :>)
I remember reading about Purdue wanting to offer a graduate degree in demolition/engineering if they could get support for the department.Contact them.dk
Purdue has a demolition program. The U. of Missouri Rolla has an explosives engineering minor. The Hong Kong Polytechnic University has a demolition certificate as does the Royal College of Military Science at Cranfield in the UK