The late Derek Bell reckoned that slip jigs were the oldest form of dance music in the Irish tradition. A useful piece of advice I had years ago was to count each bar "one-and-a two-and-a three-and-a...", which puts the emphasis in the right place and doesn't leave the player bound by the strict intervals of the notation.

Remember that just because it's in 9/8 doesn't necessarily make it a slip jig. Swarbrick and Carthy's 'Byker Hill' has been mentioned (is that in 9/8?), and another good example is 'The Famous Flower of Serving Men'. I've never quite worked out how to count that, the nearest I've got is something like '1-2-3-4, 1-2-3-4-5' etc., but I'm not convinced that's right. Carthy of course is famous for playing in single-beat bars, giving him infinite flexibility to construct the rhythm, placing emphasis where he thinks it best suits the piece .