For moves that do 150 damage, 90 accuracy, requires to recharge, can they be critical hits, super-effective and STAB?
Eg. Diagla used Roar of Time, 150 damage, critical hit, Super-effective and STAB
Just like any attack with a Base Power; yes.
In your example, you're completely right! Roar of Time will hit other Dragons for Super-effective damage, gets STAB from Dialga's Dragon typing, and can be a Critical Hit if you get lucky.
Yes, of course it's possible! you can get a critical hit, super effective, and get a STAB on Roar of Time! however, as you know, HyperBeam is a normal type. so, you only can get a critical hit and a STAB on HyperBeam...