Thanks for your help!
Given a text frame called myFrame, here's one example:
Thanks for the quick reply!
I don't know if it's because i asked for help on a blog and here, but in the meantime i found my solution where it was obvious to search (and where i didn't went before): the InDesign_ScriptingGuide_AS.pdf file ;-)
Here it is in Applescript for the record:
set TextFramePref to text frame preferences of parent of myTable
set auto sizing type of TextFramePref to height and width
set auto sizing reference point of TextFramePref to top left point