Well the
first and
second Genesis of Aquarion soundtracks were that way too. A number of vocal tracks (insert songs) mixed in with the BGM tracks. Since this is being listed as a soundtrack by retailers and is priced the same as original Aquarion soundtracks, it's natural to assume this is a soundtrack.
I watch this and there have only been 4 new vocal tracks so far (2 inserts, 1 OP, 1 ED). They're probably just noting that these songs will be included on the soundtrack.
Also, Yoko Kanno is listed as the album artist. If it were a vocal album AKINO would be listed as the album artist (since she sings all the songs for this series).
Oh, and Amazon updated this recently and changed the title from "TVアニメーション「アクエリオン EVOL」(タイトル未定)" to "アクエリオンEVOL オリジナルサウンドトラック".