The question of whether 1:30 is sufficient time is one of risk tolerance on OP's part. If he does not board his DL flight, DL will cancel his ticket and that ticket will retain whatever value it retains under its fare rules, likely $0. Same for the AS ticket. That can be very, very expensive. But, it is really up to OP.
Generally, on separate tickets where the onwards ticket is the more expensive one by far, I would advise an overnight. All it takes is a touch of bad weather and one is really stuck.