In volume 3 Tomozaki rejected Hinami's mission which forces him to confess to Kikuchi during their fireworks festival date (because their ship sails smoothly more than what she had expected). When Tomozaki confronted her about her method that feels insincere, it triggered a fight and they broke their ties. Tomozaki back to usual self and shut himself during summer holidays, not caring about his surrounding due to depression. That's when Kikuchi came to save him, with her wise advice, Tomozaki patched his friendship with Hinami again by challenging her in the game of life. He challenged Hinami that he can beat her in game of life by enjoying the game, not just pursing the META alone like Hinami. So, they rekindled their friendship again, Hinami still gives Tomozaki advice from time to time, but he also learned many things from his friends like Kikuchi and Mizusawa.
That's why I advised people to go read the first three volumes of LN because it's only the prelude/introduction for the series.
As for the romance itself, it was clear if you read the LN that Tomozaki and Kikuchi loves each other, and in volume 7 Tomozaki confessed to Kikuchi and they started dating. Hinami and Tomozaki's relationship has always been the same, a friend, a teacher, and mostly a rival.
Hinami also has a backstory that not fully revealed (I suppose) until volume 9, which I haven't read yet. But there are two chapters dedicated in volume 6.5 and 8.5 which tells about her past, which are told from third PoV as to avoid to reveal's Hinami's emotion. It was clear to me that the author was holding back for the penultimate moment that seems to be revealed in volume 9. The author says if you're reading it while watching the anime/reading the early volumes, you'll understand Hinami's motive and action. From what I heard, many people who have read it praised it as another turning point of the series yet again, and the culmination of the story so far.