The NHL games this season will be available on NHL.tv, as always. I already got my renewal notification (prior to the season being announced, actually, so that made it pretty obvious they were getting close).
As far as the World Juniors, I'm not sure. If you're in Canada, the TSN subscription should get you access to watch them online (at least the ones TSN is covering, which I assume is all of them). Unfortunately I'm not in Canada so I'm not sure where I'm going to go. Might end up having to use some shady streaming service, as usual. It sucks. Just not a big enough deal down here for any of the standard streaming services to bother carrying them. I really wish the IIHF and NHL would partner to show them on NHL.tv.