How to get user id of order from order entity metadata wrapper
It's the same as any property on a metadata wrapper:

$uid = $order_wrapper-&gt;uid-&gt;value();



  Or should I think of loading order object?


You can't have an entity metadata wrapper without an underlying entity, so the object you're referring to is already 'loaded'. You can get it with

$order = $order_wrapper-&gt;value();