No, it’s not possible to take the ABST/AIT or any other province BST exams online. You go through the following process to get Security Licence or Investigator Licence.
1- Complete Online or In-Class 40/60 hours course for ABST or AIT
2- Appear in Final paper based/computer based Provincial Exam
3- Pass Provincial exam with 80% and some of the provinces 75%
4- Get Police Clearance / Background Check
5- Pay Licence Govt. fee
7- Fill Licence Application and Apply for Security Licence