DLsite: https://www.dlsite.com/maniax/work/=/product_id/RJ01252355.html
DLDShare (dlsite alt): https://dldshare.net/archives/806585
VirusTotal Live2D: https://www.virustotal.com/gui/file/b2fe0f8cd0adb1d221d662e5f33b36b8245413178d8986b0d6dd3c42fc6d78de?nocache=1
VirusTotal IllustOnly: https://www.virustotal.com/gui/file/b2fe0f8cd0adb1d221d662e5f33b36b8245413178d8986b0d6dd3c42fc6d78de?nocache=1

Taken from hentaibanchi.
It's 9 GB because there are 2 versions of the game inside: animated and illustrations only, although in the animated version, you can turn off the Live2D in the options, which is very weird to have a duplicate of the same game, just without animations in the options.

Important note: the fps drops are really bad in the animated version during fade transitions or when you open/close the menu, while the IllustOnly version is smooth.

Slow seeding at first.