Yes, Cavs are very prone to needing their anal glands emptied...and each is so different so you will just have to see through trial and error how many times your needs them done. Brooklyn is at about every 8 weeks, I have friends that are 6 weeks and every 3 months. So, I would bring him in, say he is scooting again and the vet will empty them. She will be able to tell you how much comes out (1/4 full, 1/2 full, totally full) and then you will know "okay, this is how often he needs to go, or I could have waited "X" number of weeks if they were only 1/2 full".
Also, Brooky tends to scoot a lot anyway, even after we get her glands done. Some of it is a bit habitual (I think we gave her attention when she was little, like "no! not on the carpet"
and that can feed into it. Best thing is to ignore the behavior or distract without giving attention to it. But you need to make sure they glands are not full again and the he is wormed. You could talk with your vet about other things it could be too...allergies, etc.
Also, once I realised that I needed Brooklyns emptied every 8 weeks, I just make a standing appointment with a vet nurse there and she does it...much cheaper. And if you just say it is for an anal glad empty ONLY, they will work something out and not charge you a full appointment. Talk to your vet about it and tell him/her that you would love to be able to make an anal glad only appointment and how you could work out costs.
While they are this young though, you are in the vet a lot anyway, so just always have them emptied while he is there whether they are full or not