For example youtube.com/opener - it won't play via the browser, but I can't figure out how to access it via the app.
Is it possible?
You can't. This feature was added in the ICS version of the YouTube app. Older versions don't support it.
Check how you are looking for it in the app you have a couple options you can try:
From the regular youtube.com/opener site subscribe to the channel
or
From the app search for the AlterArt2 channel and subscribe to it
The channel isn't actually listed as opener it is under AlterArt2 so watch that to make sure you are able to find it. I located it on my youtube app and was able to subscribe and view. I'm using an HTC One X ICS.
Hope that helps.
It seems that if you add the livestream to your Watch Later list, you can then view it via this on your mobile device. However, it will start from the beginning of the stream and it seems you cannot forward it. You can pause it, but I found that if I left the application, when I would go back it would take me all the way to the start again.
Maybe this can help someone somehow.
You can use the browser.
Just type the livestream link, and it will load normally. On the downside, it will lag a little bit.