You are spot on. And if you look at the Line 6 response in one of the other threads on this topic you'll see that they're doing everything they can to avoid blame and to point the finger at others. As for other apps having problems with IOS 9 (and every IOS upgrade), the difference is: 1) most of those apps released fixes within days of the release of IOS 9, and; 2) most are noncritical apps in the sense that users don't rely on them to control external hardware and systems. I don't care if 7 Little Words doesn't function for a day or two, but it's whole 'nother ballgame when my $400 Amplifi 150 and $200 Amplifi TT are rendered useless because Line 6 can't get its act together.
Oh, and as a beta tester for IOS 9 on both my iPhone and iPad I can say I haven't had any problems with any of my other apps even since the appearance of the first beta or any of the subsequent updates. Amplifi Remote is the only app I've had problems with. And finally, as a user of Line 6 products since the original Axsys, this is emblematic of their customer service and support: it's always been abysmal.
I won't be considering a Helix. That's too much money to dedicate to a product that's likely to be unreliable and lacking in service and support. The Axe FX and Kemper products are more expensive, but you get what you pay for, and that's what I'll be looking at.