Futaba sais don't turn on Tx with antenna collapsed?!?
I don't know what the inside of the 9 looks like, but with a warning like you say, it is probable that there is no connection from the RF amp to the antenna until the largest section is pulled up to make contact. This has been done by some manufacturer in the past, but I do not remember which one. With the 8U, there is always connection.
Les