You should always check on Wishes cruises, because Disney can change the time of Wishes to better suit a sudden spike in attendance. So 8pm can easily become 9 or 10pm on short notice. Alway plan to arrive at your dock at least 1 hour prior to the scheduled fireworks.
Now, IllumiNations is a different story. IllumiNations is almost always at 9pm. Here are a couple exceptions. Currently, IllumiNations is at 8pm on Friday's only. This started Jan 2009 and was said to run "until Spring Break" so this should be very soon, so check often. After Spring Break, well who knows for sure.
OK, and starting the day AFTER Thanksgiving, IllumiNations moves to 9:30pm so as not to interfere with the Candlelight Processional at the American Gardens Theater.
Finally, NYE almost always had two shows, one at 7:30 and one at 11:30
Again, plan to arrive at Bayside Marina at least 1 hour before the scheduled performance.
Like everything else, anything and everything is subject to change.