This unpublished manuscript of Grothendieck's was given to me by Messing. It shows that, contrary to numerous statements in R&S, he himself called them "catégories tannakiennes".
On peut dire que pour l'essentiel, le livre de Saavedra est un exposé en forme soigneux et circonstancié de mes idées sur une sorte de "théorie de Galois-Poincaré" de certaines catégories (que je n'aurais jamais revé appeler "tannakiennes". . . ) (R&S, p. 1160)
It can be said that, for the most part, Saavedra's book is a careful and detailed exposition of my ideas on a kind of "Galois-Poincaré theory" for certain categories (which I would never have dreamt of calling "tannakian". . . )
Grothendieck also forgot that he had attended Saavedra's thesis defence.