How can I get TV-out from a Galaxy Tab 8.9? I am using a Samsung Galaxy Tab 8.9. I would like to mirror the screen on my TV but I could not find TV-out in the Settings.

How can I do this?
Since the Tab 8.9 uses a proprietary connector (as do other Samsung tablets), you need to use an adapter that they provide. These could previously be purchased direct from Samsung, but have since been discontinued. Resellers now list a wide range of pricing on sites such as eBay. There was also an even older RCA adapter made by Samsung, but the Tab 7 Plus, 8.9 and 10.1 don't support it, to my knowledge.

At that point, I believe it works like other Honeycomb tablets in that it will simply mirror to the TV automatically after being plugged in.

The only real alternative would be to use your computer as an intermediary device, along wish some software that allows you to cast/record your screen. There are a number of options in How do I project the screen of my Android phone for a presentation? that may be worth investigating.