I do think people should consider the issues with Sousuke embracing a quite fundamental level of self-deception, down to the soul, at a time like this. Whether it's conscious or not, that's still what he's doing.
This is a character defining moment, and he shouldn't be running and hiding from the truth here. Particularly after just fighting the embodiment of deceit.
The results of being sincere may be difficult, they may be challenging. Is that a reason for a true samurai to refuse to do them? Sousuke's actions were those of the sun. As a result, so should his words.
Sousuke has something of a tradition of bending the truth in service to being more honorable elsewhere. Also, I think that it's being misinterpreted a bit.
- We've known in-character for some time that this was A Thing. We didn't know what caused it, but it sure wasn't normal, and we've definitely had some implications that it was Sun-related. (We still don't know who that woman was, but Amaterasu was a not unreasonable thought, and "overwhelming heat and fire that scourges the enemies of Rokugan" is enough oriented to the sun that you have to at least consider it as an option.) Also, that whole "Yakamo was the Sun" thingis pretty deeply ingrained in Crab Clan culture. "This somehow came from Hida Yakamo" had to be somewhere on our list of plausible explanations even before the shadow-guy said anything.
- We know that remaining silent is, essentially, asking the Master of Fire to besmirch his own honor for us. That's the sort of thing that Sousuke generally isn't okay with.
- We know that claiming to *be* Yakamo or *be* the sun is likely to produce quite a lot of Drama very quickly, and distract from our mission. If it turns out that we're wrong, it's also likely to do Bad Things socially - to us, to the mission, and potentially to the Clan. Suggesting that we were merely empowered by him, though, is a lot less threatening.
- Maybe the shadowspawn lied. Maybe he spoke truth. Maybe it was a mix of the two (that last is popular among manipulative villains). We don't know.
My take on the vote is that IC, we don't know, and we know we don't know. Our best guess is that we're somehow the reincarnation of Yakamo, but it's entirely plausible that we've just been blessed (heavily and painfully) by him, or that this is something else sun-related (Amaterasu? The Jade Dragon?) or that this is something else altogether. We know that we don't want Akio claiming it, because that *would* be lying (and we don't want to be the cause of his dishonor), and he'd probably be found out later when we did it somewhere else (and we don't want to be the cause of his shame). At the same time, we don't want the arrogance or the potential social downsides of claiming that it was us - at least, not until we know more. Suggesting that we think it a blessing of Yakamo isn't technically lying, it gets Akio off the hook, and it limits the disruption that might result until we can talk with our Boss and/or the Kuni about this and come up with a plan to handle it properly. It's also an easy supposition to walk away from if it turns out that we want to out ourselves as his reincarnation or something - Obvious Solar Darkness-smiting coming from a Very Hida Bushi? Why *wouldn't* we think it was Yakamo blessing us in some fashion?