...again, or, instead
Okay, I invented enenēkosioienenēkontaenneamania on the analogy of hexakosioihexekontahexaphobia. But of course the hex word refers to the number 666, six hundred and sixty-six, and the mild hysteria that surrounded June 6, 2006, which was probably largely media-inflated ("Okay, guys, there's got to be a few looneys out there making a stir about this; let's go find 'em!"), is about the digits as digits. Whereas the 9/9/9 thing is just about the date, with no reference to the digits of the number. So instead, I give you-
trisenneamania