There is no direct way to get access to the entire pokebank without actually paying for it. You can come close with phbank (a homebrew alternative) and by using pkhex for transferring (requires twlsavetool to extract ds save files).
That requires you have an NDID linked to a Dev console.yes, use ecfundtool dev app
some guy on a rom site got it working on retailThat requires you have an NDID linked to a Dev console.
I call bullshit.some guy on a rom site got it working on retail