
Technically it was never explicitly stated (as he doesn't have an official music video) but I do agree with you that it strongly hints at it in his character song.
I could only find a cover version since the song is suppose to be album exclusive at the moment but there are some hints in it which can be taken as canon evidence (since Capi is related to Honeyworks and Yamako did do the illustrations for the video)
https://www.youtube.com/watch?v=ufo2Evaz5nw
Anyways here's my evidence
- There's a scene with a photo of the original set of members, suggesting that his crush is a senior.
- The fourth line in the lyrics where Kodai refers to himself as あなたに恋した "年下" (the "younger [classmate]" that fell in love with you) further backs it up.
- In the second verse the first line says 幼馴染でも同じクラスでもない ([we] are/were childhood friends but we were never/aren't in the same class). Out of the original group, the only one that is known to have a relationship with him is Natsuki because his brother is his friend.
- Finally in the last line of the first chorus it says 無邪気に笑うあなた夏のように (The you that laughs so innocently is like the summer). Natsuki's name has the same kanji for summer in her name
Only when honeyworks decides to release an official music video will we be able to say 100% that it's her but I'm 99% sure it is her
Someone who has seen this movie that can clear my doubt.
Kodai Yamamoto, Kotaro's friend.does he have a crush on someone? Because I think everyone has a crush on someone