Indeed but the texan was developed from it, it is different from a PC-9 as the Shorts tucano is different from the original Emb-312 tucano.
but i'll put some figures here...
The PC-9 project is quite old, researching here i found that it was introduced in 1984 , as the Emb-312 was introduced in 1983. both were designed as a trainer aircraft primary.
The EMB-314 Super Tucano had the devlopment started in 1998 and enter operationally in 2004 a advanced trainer and a counter-insurgence airplane , specifically designed to fight the narc guerilla in south america amazon rainforest , in which it had a proven sucess doing this mission busting illegal runways, shoting down narc planes,recon and bombing missions over narc bases.
both aircraft are good however, tucano was totally made for the mission since it was devloped with such mission in mind, integrating all the systems to be ready for smart weapons.
funny a memory i had of a super tucano flying over my head last year while barack obama was visiting brasilia, about 3 different aircraft were searching the city with its cameras to suspicious activities, two days before and in the day that Obama stayed here.
ST in combat (retrieved from the wiki)
well, that's just my two cents - two different aircrafts designed for two different missions.