For any non-Canadians who aren't getting much Canadian news, a brief round-up: The shooter was a homeless guy, with a prior criminal record in Quebec and B.C.. He apparently had drug issues and mental health problems. He had recently spoken to his mother, for the first time in five years. She made a tearful statement saying that she was crying for his victims, not for him.
His criminal record in B.C. included trying to rob a McDonald's with a pointed stick, and on several occasions he is said to have stated that he wanted to be arrested so that he could get help with his drug problems. So this was maybe more of a desperate escalation than a terrorist attack?
He was apparently a devout Muslim, in that various people who remembered him from homeless shelters remembered him as always finding a corner to spread something for a prayer mat at the appointed times for prayer.
On the other hand, the imam of a local mosque said that he was asked to leave when he disagreed with their policies: the mosque was in favour of outreach to other faiths and being part of the community. He, apparently, felt this was weak and inappropriate, and told them to shape up, and was invited to leave.
And, barring further news, that appears to be it.