I did a little research on it as I was surprised to see Apple included the iPad 2 in their iOS 9 update. It being the older of the iPads and they didn't include the iPhone 4. Anyway, seems there is an issue for making the video bigger on the iPad 2 with this upgrade, actually seems to be all iPads at the moment, from what I'm reading. No solution yet. You'll have to wait for apple to send out an new update that will fix this.
One person mentioned using the Zoom function in Settings to make the screen bigger. It's not perfect, but it's a workaround!
[ Last edited by shinny at 10-8-2015 00:02 ]