Kim Eana (IU's lyricist), Park Yohan (IU's dancer) and Hanteo manager have 评论 on her 照片 (I'm way too lazy to scroll all the 评论 looking for 更多 people I know.)

She is also following several people, like Coordi Noh, that require approval to be followed.

IU's confirmed Instagram account: link

[UPDATE] IU's former producer, Cho Young Cheol, confirmed the account on his twitter via his Instagram: link and 李知恩 replied.

Translation here: link

照片 caption translation:
ee ji geum (wordplay of ‘Lee Jieun’, meaning ‘this now’) Instagram. Why does everyone add # at the back?

trans source: link

照片 source: link