Do i have to have my humax pvr9300t switched on to record ?

Yes it does record from stand-by.

This happens whether or not you have selected the power saving option from the menus.

If you are using padding then it will start recording the selected channel at the appropriate time.

If instead of padding you have the recording options both set to 'On Time' then the 9300T will keep an eye out for the start of the programme 15 minutes before the scheduled start time.
I have had some rare issues when I have brought the 9300 out of stand-by then back into standby within that 15 minutes.

If you use Series Recording and are away for more than a week you will need to enure that it keeps its electronic programme guide up to date. This is only a concern if you have very few timers set. If you only record the occassional programme then you could use the menu option that Powers On and Off to tune into BBC 1 once a day for updates. This option is located within the Time Setting menu.
But if you use repeat timers instead of series recording there is no point doing this.

NS
February 2012