Final answer:
Regions that historically have populations with 9 as the power of 10 in scientific notation, based on the context provided, are Africa and Asia.
Step-by-step explanation:
The question asks to arrange the populations in scientific notation based on their powers of 10 and identify which regions have populations with 9 as the power. The reference information does not directly provide the populations in scientific notation, nor does it specify the precise current populations for each region. However, historically, it's noted that Asia, particularly China and India, have had very large populations. If we were to use historical context where China led with 125 million and India had about 90 million, these numbers would have 9 as the power when written in scientific notation (1.25 x 108 and 9 x 107, respectively). Therefore, given the historical context and assuming the student is looking for regions with historically large populations, the regions with populations having 9 as the power of 10 would be in Africa and Asia (Option A).