Autohypnosis is a handy little skill that basically:
- Means you never die to bleeding out.
- Can act normally while at 0 HP.
- Can resist Poison somewhat better.
- Can get a reroll vs. Fear.
None of those are particularly important for a Barbarian. It's a handy skill to have if you have extra skill points (basically, it just means you have a disciplined mind that's capable of shrugging off pain and such). You probably won't, here.
Acrobatic Backstab, sure, knock yourself out. It requires 12 ranks in Tumble to pick up though; earliest you can have that is character level 9 (then you can have 3+Character Level = 12 Ranks in a class skill). It also doesn't work with a full attack (since you need to move to use it) so you'd best be a Warblade to use it (basically, you only get extra attacks from high Base Attack Bonus and any bonus attacks you have on a full attack; doesn't matter for the first 5 levels unless you take Whirling Frenzy, but after that point you want to stand still to dish out maximum pain).
Warblade maneuvers can be used with movement tho so that's away around the scarecrow syndrome of having to stand in place to be useful.
In general, skill tricks are handy but not so big. Just pick ones that feel cool to you up if you have the skill points.