In my opinion, they should call the next product "JD Edwards EnterpriseOne R10"
"B9" was code-name for..."ERP 9".
Before the Oracle acquisition, PeopleSoft had not yet released their "PeopleSoft Enterprise 9.0" product, let alone "8.9".
PeopleSoft Enterprise 8.8 was the order of the day in late 2003. EnterpriseOne 8.9 went GA early September 2003 (five years ago...wow.)
The directive from the PeopleSoft "tools" was to rename the JD Edwards product "PeopleSoft EnterpriseOne 8.9", such that it matched the PeopleSoft naming convention and didn't get a "leg up" on their Enterprise product. Thus, when Enterprise 9.0 shipped, it was "superior" in name and number to EnterpriseOne.
This made sense for both PSFT and JDE, as 8.9 was in between B7334 (8.0) and 9.0 (B9), while fitting right in with the PeopleSoft products.