How to specify the target directory with mv?
As you are using the GNU version of find you might as well use a GNU version of mv which will understand the -t argument.
Under Macports and Homebrew mv is part of the coreutils package and installing that will put gmv on your path.
Macports installation is by
sudo port install coreutils
gfind path_A -name '*AAA*' -exec mv {} path_B/ \;
should work, you can even use find as long as you don‘t need any special functionality only gfind provides. You can also basically use any other answer in the Q&A you link to in the question :-)