So with a human wanderer monk can I use that body shield feat to hold someone and just wander around stealthing?
It would help if you would post the specific rules you're asking about.
Outside of whatever a wanderer is, the Body Shield feat only grants you cover against a single attack. I don't think this counts as finding cover in order to use Stealth while directly observed.
Disappear Unnoticed (Ex)
At 12th level, the wanderer may use Stealth to hide even while being directly observed or when no cover or concealment is available, as long as he is adjacent to at least one creature of his size or larger, by spending 1 point from his ki pool. This effect lasts until the beginning of the wanderer's next turn and may be continued in consecutive rounds by spending 1 ki point each round.
This ability replaces abundant step.
It's not the cover he's wanting from the Body Shield feat, but the ability to carry somebody around the battlefield, basically being invisible while doing it, because by carrying somebody, he'll be "adjacent to at least one creature of his size or larger" by default. Given the wording of the Body Shield feat, I'm not sure why it would even be needed for this move to work. Just grapple somebody and win grapple checks each round to move them against their will.
Grappling is an attack, and you cannot use Stealth to hide while attacking (except for sniping). This is a restriction of the skill separate from the observation and cover/concealment criteria.
Okay can I just carry a corpse then lol?
I know it's not rai..
A corpse is an object, not a creature. ;)
As long as you're adjacent to an ally or enemy of your size or larger, you can spend 1 ki point and try to hide. At the start of your next turn the effect wears off unless you're continuing to burn ki, so you'd better have cover/concealment at that point otherwise you no longer qualify for Stealth to remain hidden.
The real limiter of the ability isn't requiring an adjacent creature but the ki expenditure. Using the ability repeatedly in combat to mimic HiPS is going to burn through your ki pool pretty quickly.