I would wait at least another 9 months before getting an anemone. They are VERY finicky animals and do not like unstable water chemistry and will quickly die if stressed. When they die, they disintegrate and fould the tank quickly. I have read stories on here of entire tanks being lost due to a dying anemone.
That being said, if you can wait they are beautiful animals, Mine has found a home in the crevices of a nice piece of LR
and has great bubble tips when the lights are on, and stretches out when the moonlights are on with his tentacles in the current. He hasn't bothered anything.
If you are worried about wandering anemones, there is not much you can do abut that, they will go where they want to. You can encourage them to move from a spot by pointing PH in that direction and making it uncomfortable for them, but I wouldn't try to pick him off the rock, if you damage his foot, he is as good as dead.
Now if you are worried about him wandereing around your LR
, you can do two things that might help;
1) Get an LTA which likes the sand
2) Get a BTA and build a bimone(sp?) in your tank (essentially, this is a a pile of LR
with a bunch of crags and crevices separated from the rest of the LR
structure by a patch of sand). The bimone is meant to give the BTA a nice comfortable place to call home where he can hide his foot from the light and discourage him from moving, b/c as I understand it, they don't like to move across the sand.
But step 1 is to wait for your tank to mature a little more.