The French grades have been pretty universally accepted for bolted sport climbs in the UK now, including walls (gyms). Below 6a though, the a's b's and c's have been dropped and replaced with a "+". So the equivalent UK grade for a 5.9 bolted sport climb would be about a F5+ (the F just stands for French).
For Trad climbing the British system is a bit complicated, which leads to lots of fun debating what grade a given climb is - just try googling "three pebble slab" and you'll see what I mean. TPS is only about 30 feet high - if you printed out all the debate about its grade you could stack that higher!
A 5.9 trad climb would be somewhere around a HVS 5a though if it was a bit bold, or particularly strenuous, it might get E1 5a.
US 5.9 is roughly equivalent to Australian 17 btw.
Chart here: http://www.alpinist.com/grades/
The randori aspects really start when birds fly over and drop rocks or goats object to your presence.
Wow, what kind of birds are those?
There are birds (Fulmars) on sea cliffs here (especially in Scotland) that defend their nests by projectile vomiting horrible green stinky bile at you, but I've never heard of actual avian bombing runs.
The biggest parallel between aikido and climbing for me?