unless they have a major change or a major collab under wraps it's like going to be a quiet season with more low activity like 7 and 8
they either need a pve activity flood or a game changing approach to a session that really motivates long term players, not just cheesy convenience stuff, actual motivation to consistently participate. Not just throwing in another world event or something that people aren't going to do beyond a couple of weeks.
What will be important is how they implement things they put in the game and how they react to bugs and major feature issues. They don't have a great record on either of these so hopefully that improves in 9.
7 and 8 both suffered greatly from priorities not being focused where they needed to be to keep activity alive and from how they implemented the changes.
Hg has a tremendous amount of burn out in it right now, there are some other games people are getting into as an escape from SoT frustrations, hopping pvp is going to return and run off activity during season 9. I wouldn't buy into too much hype that people often push right before a season, sets expectations high and just leads people to grumpily communicating their frustrations based on disappointment from over-hype.
They have people sharpened and battle tested exiting HG and looking for action, they likely made the issues worse long term for a short term break as they only buffed quick action play.