House built in 2008. First noticed this problem in the kitchen a year or two ago. Ceiling has wood trim along the top, but it looks like either the trim has shrunk (because its wood) and caused what appears to be a split in the drywall along the edges. Have noticed this crack forming in other rooms too, along the line where the trim meets the drywall. Just paint over it?
I don't see anything concerning here. Built in 2008 there has been some settling and a number of annual cycles that cause wood to shrink/swell.
I'd do nothing at my house but if this troubles you some interior caulk applied along the border would cover this up.
This all assume that the moulding is still firmly attached. Check that it's not loosened up over time and re-fasten it if necessary.