The best way to test a 240v linear transformer is to power on. Of course you can test the ohms of the winding for the primary and secondary side but measuring the input and output voltage by far the most accurate method. You must have the courage to test it if you are a beginner or else get someone who has experienced in the electronic repair field to guide you.
Place you analog or digital meter to the input of the transformer and make sure there is 240v entering in. If no voltage then begin to troubleshoot upward until you managed to find the fault. Assuming the input measured 240v, now you have to check the output. If the linear transformer output stated 9 v ac then you should expect a little higher ac at the output (say may be 9.8 vac and etc). Once you got the ac voltage rating then you would know that the transformer actually working. Note: please do not perform this kind of test on switch mode transformer because if the switch mode transformer do not have load on it, it will blow the whole power section!