Even if this name was not granted officially, but, as is very common in legions named after peoples and countries, was given by other soldiers at its arrival in another part of the empire, after coming from Spain, the end result cannot be refuted: this legion belonged to a Spanish army early in the Imperial Age. To a certain extent this is confirmed by the following inscription Ephem. Epigr. VIII nr.530: “M. Aemili M. f. Pob(lilia) Soteriae equities domo Oscensis…veterani leg. VIIII Hispanie(n)s(is)… The Spanish homeland of this soldier is understandable if the Legion was in Spain when he went into its service. Subsequently, certainly still under Augustus, he settled in Cales as Veteranus and or is shown to be) of the Tribus Poblilia, related to this city, and not Quirina, the Tribus of his old fatherland. (different explanation in Von Domaszewski Bonn. Jahrb. CXVII 68.9)
But a little while after the crushing of the greater part of the Spanish rebellion in 19 BC, the legion was sent to a different theatre of war, Illyricum, where we already find its nickname Hisp(ana) on an early tombstone (CIL V 911). Literary records however begin only in 14 CE (Tac., Ann. I.23 and 30) but some of its memorials surely belong to the Augustan age. A fragment  (CIL III 13977) from Gardun in Dalmatia belongs in the period before the division of Illyricum, which took place during the great Dalmatian-Pannonian rebellion in 6 CE: Sex. Cornelius Sex. f. Camilia Nonanus veter[anus…], if it were certain that Nonanus here refers to a member of the VIIIIth legion. After the division of Illyricum, Leg. VIIII was allocated to the army of Illyricum inferius (=Pannonia). In Aquileia, the road junction and military support and jumping-off base for all operations in Illyricum, several early tombstones of soldiers of Leg. VIIII have been found (CIL V 911, 947, Pais Suppl. P.24 nr. 180; likewise from Histria CIL V 8197, the stone of the Centurio CIL V 906 is younger). In the period before the installation of an Imperial Province Illyricum, while only a single commandant was in command of the Exercitus Illyricus here (Arch. Epigr. Mitt. XX 1897, 1-4), Aquileia may continually have been a legionary camp as well. But later, from 11 BC onwards, all legions were transferred further inland.
In 14CE, the three Pannonian legions were together in one summer camp (Tac., Ann. I.16), but were in separate camps in winter (Ann. I.30… suis quisque hibernis redderentur) and therefore marched out of the summer camp one after another. The VIIIIth will have stood along the rivercourse of the Save, surely in Siscia, certainly no further downstream.
In 20CE the legion was transferred to Africa as reinforcements for Legio III Augusta, as the troubles with the Numidian Tacfarinas could not be repressed definitively. The legion met with Calpurnius Piso, who had been called away from Syria, on the Via Flaminia (Tac., Ann. III.9). On this episode in the legion’s history, see: Cagnat, L’Armée Rom. d’Afrique² 13.19.10f.