Here are the certification dates, according to
www.riaa.com:
April 25, 1996: certified 5X platinum
September 19, 1996: certified 6X platinum
December 9, 1996: certified 7X platinum
June 16, 1998: certified 8X platinum
June 18, 1998: certified 9X platinum
I'm certain that over the past seven years, All Eyez on Me has surpassed 10X platinum, but the certification process is not automatic. The record companies have to pay a fee to the RIAA for them to go back and count the exact sales and provide an official certification. The fee is the same whether the certification involves multiple certifications (in this case, it happened in the initial certification which certified the album having gone gold, platinum, and 5X platinum) or if there are no certifications at all (if, in the highly unlikely circumstance, the album is still at the same level).