[curt.clifton]

These are buried deeply in the menus. See Edit → Outlining → Move → … The keyboard short cuts are listed there, generally they are Cmd-Ctrl-arrow

Also, the "hotter" keys from OmniOutliner generally work when you have a row selected, but aren't in editing mode (that is, no blinking insertion point):

u - move item Up
d - move item Down
l - move item Left
r - move item Right