| RuyanVe |
Taken from the Dragon Disciple PrC:
PRD wrote:
Spells per Day: At the indicated levels, a dragon disciple gains new spells per day as if he had also gained a level in an arcane spellcasting class he belonged to before adding the prestige class. He does not, however, gain other benefits a character of that class would have gained, except for additional spells per day, spells known (if he is a spontaneous spellcaster), and an increased effective level of spellcasting.
Emphases mine.
So: no. The prestige classed illusionist needs to gather eight levels of illusionist under his robes to get access to the school special ability.
Ruyan.