chapter9 will be the last chapter, and 8 chapters were already released (chapter8 is currently on patreon only). i dont think that there will be a way to have all the chapters merged into one download since the game got really big as chapters were added, and there is a limitation on file size on itch. becoming a vanir backer on patreon is a good way to buy all the chapters in one go (you still need to merge them manually).
there is a plan for a prequel to the game, a trailer was released, but for now the focus in on finishing this game.