With the just number of 9" fish you mention, a 240 will already be overstocked, and most will have a lot of growing to do.
The way commercial aquarium filters you mention are rated, those ratings are for the average aquarist tanks with a few angels, small gouramis. and other bread and butter, small community fish.
They are not rated with the fish you want in mind. So throw those numbers out the window, as grossly inadequate.
At adult sizes with just the stock you named you are going to need to do large daily water changes to keep them healthy no matter how heavy the filtration. Filtration only does so much, it does not reduce nitrate or other build up of waste chemicals you will need to dilute to keep water looking good, and fish in good health, especially if over stocked.