How long is usually between listing a robot under particiapants and having it participate in roborumble?
It depends on whether people are running RoboRumble clients, but I can see (here) that some people are, so it should be pretty quick. I checked your bot and was able to fix the Dropbox link - it needs to be a download link directly to the JAR. Hopefully that does the trick. Good luck in the Rumble!
There is something wrong with you bot. I see the following line in the roborumble console
Participant ignored due to invalid line: Grystrion.Grystrion2_1.0
Once you submit your bot to the wiki, it is good idea to run the roborumble on your own computer. Firs of all, you see if the roborumble can download and execute your bot. Secondly, you would help to run the competition, easing the load from other people CPUs.