Actually i think 9 is less secure than others. Because you are publicly showing up yourself as someone who has something to hide. I'm sure satoshi has no heavily guarded fault. And he is the richest bitcoiner alive. And he probably is way more safe than the operator of a big mining farm. Even with guarded vault.
Maybe if you are a private person you can hide it, but what about a big company?
They use 1 primary address for identification or accounting or whatever. All their transaction is traceable, and if they store billions in another address, they can be caught very fast.
Their CEO or Security officer can be extorted, how will they protect against that?
Sure, though they have insurance. And the fiat bills have to be physically moved. When exchanged they can be found via serial number. It is no fun washing such money... i imagine. No problem at all with bitcoin.
Even if you have a bunker your relying on guards who I would assume make much less then what is being stored. As long as there is greed there is a chance of them going "bad"
Actually private security guards are much more disciplined, in many cases than military guys.
Private security guards are ex-military, veterans, disciplined, loyal, and work for big money, so they have an incentive to not fuck up, as they also have a reputation.
Average military guards may be recruits with little experience, and the military salary is little, so they can be corrupted more easily.
I think that theory is wrong. Blackwater... or The Rock, i believe, they are named now, hire such ex military. But these guys are EX for a reason. The end result is that the US government hires these soldiers to make war and these guys regularly are involved in killings of civilians and such things. These ex soldiers often enough are psychos or have some kind of problem.
Having to trust someone is always a risk