What Counts As A Destructive Device
Destructive devices include explosive, incendiary and poison-gas devices, plus large-bore weapons other than shotguns ATF has found generally recognized as particularly suitable for sporting purposes. They are NFA firearms, so registration and transfer rules apply.
License Plus Tax Status
The Type 09 fee is $1,000 per year, three years at a time. Dealing in NFA destructive devices also requires Special Occupational Tax registration — a Class 3 SOT on top of the license — filed on ATF Form 5630.7.
Practical Reality
Most applicants who think they need a Type 09 actually need a Type 01 plus Class 3 SOT for ordinary NFA items such as suppressors, short-barreled rifles and machine guns. The Type 09 is only for destructive devices specifically.
Fees, forms and processing rules change through ATF rulemaking. Confirm current requirements with ATF and your state and local authorities before you file.