Well, it looks like there may be a bug here. There is only 7 released devotion points after checking the files. The last one is in the side story that I did not finish yet. Here is a small guide though to help.
Yukine Devotion Point Locations
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1 - Coin Toss Game
2 - Converse with Yukine after having selected very specific choices after meeting back up with everyone from exploring Angel Heights with Iliff.
3 - Select a specific set of responses while speaking to Yukine in Angel Heights after everyone else has disappeared.
4 - "A little help never hurt" - Choose this at the end of Chapter 1.
5 - Talk about those 'parts' in the beginning of Chapter 2
6 - Answer correctly to Yukine's question about time.
7 - Correctly answer all the trial questions with Yukine when he's talking through the orb.
8 - [Not released] Complete the questions all correctly