Question: Are the Nine Grades (九品) of birth in Pure Land levels to pass through to reach Buddhahood there?
Answer: Based on nine sets of criteria measuring extents of spiritual cultivation before reaching Pure Land, the Nine Grades together form the spectrum of levels, through which beings usually enter Pure Land. Once the Three Provisions (三资粮) of Faith (信), Aspiration (愿) and Practice (行) are adequate, there will be birth within one of the grades.
Those of better practice are thus born from higher grades there. Although they can be referred to now, for aspiring to be born within a certain grade there, they are generally not seen as levels to advance upwards one by one upon reaching Pure Land.
Of course, there is spiritual progress in Pure Land, but the speed will be much faster than through learning and practice in our Defiled Land here, thus with swiftly progressing levels not gauged by the more widely discrete Nine Grades there. With continual practice there, one will even quickly reach the final Bodhisattva stage just before Buddhahood, which transcends the highest of the Nine Grades.
九品: 《观经》：第 - 部分
The Nine Grades: Contemplation Sūtra: Section -