Our driver/guide took us to the 6:30pm pooja ceremony which was the perfect timing as it was very atmospheric, with the light fading and the temple coming alive with the ceremony.
I would recommend having a guide to explain what is happening and to also guide you through the temple - it was very busy and could feel a bit chaotic if you don’t have someone with you to guide you through it, and to also take you to all the different rooms.
There is a dress code where you need to cover your shoulders and knees, and you also need to take off your shoes. Security is tight due to a bombing outside the temple a few years ago so give yourself time to get in to the temple.
This is a must do when visiting Kandy.