Can Siri play a recent iTunes Radio station without an Apple Music subscription?
It looks like you still can play your iTunes Radio stations from Siri. From what I understand, you're correct in your observation that you no longer can view all of your stations outside of the "Recently Played" section, but Siri can both create new stations and play existing ones on command.

I tried playing/creating stations through Siri a few times on my iPhone 6+ running iOS 9, with these results:

When I tried to play an Owl City radio station I had previously created, and told it, "Play my Owl City station on iTunes Radio," it played Beats 1. But this worked (and created a new Owl City station instead):




To make sure that things were working the way I thought they were, I also tried playing a Taylor Swift station I had recently created. This time, it played the station without creating a new one.



Unfortunately, you can't just say, "Play my most recent radio station," and expect it to play your most recent station. Instead, in my experience, it jumps to Beats 1, what Siri calls its "favorite radio station." You can see the Music app cueing it up in the background thanks to Siri's translucent new appearance.