unfortunately you won't enjoy this next solution i will offer but
try to unpair the watch, reinstall ios 9 beta 1, re pair the watch, re send the config, update to beta 2 :/
Got it!!
I was hesitant to reinstall iOS 9, beta 2 on my iPhone 6 after the initial text message crashes finally seemed to fade away, lol...
So, I removed the beta 2 Watch OS profile from my iPhone, performed a factory reset on the Watch, re-paired, loaded the profile to both... & it downloaded & installed with nary a hitch! =D
Note: I reloaded my Watch from a saved beta 2.0 backup, prior to upgrade. No issues.