Where does the Iben Ezra say different then Chazal? And could early Achronim also say different?
In many places the Ibn Ezra differs with Chazal as a commentator (but expressly writes that in no way does he differ with the halachic tradition in practice, see his short commentary on Shmot 21, 8). For example Breishit 10, 9, where he writes that in his opinion, from the pshat, Nimrod seems to be righteous (he hunted animals “before God” to bring as sacrifices), despite the tradition in chazal (and as is also pretty clear from the pshat as well, according to most commentaries) that Nimrod was evil. Similarly the Ibn Ezra understands the pshat that Hak’hel was done in the beginning of the 7th, not the 8th year (Dvarim 15, 1). But nevertheless, bows to chazal regarding what to actually do and practice. See also Vayikra 7, 25 In general, some early achronim (like the Abravanel, who no-one considers a “rishon”), also say different than chazal, while many (!) latter day “pshat” achronim, often left the way of chazal to suggest their own pshatim (especially Shadal, RShR Hirsch, RDTz Hoffman, and the Ktav v’HaKabbala), often to “answer” questions raised by Bible Critics and Maskilim.