Since installing Yosemite, the keyboard shortcuts (with an Apple wired keybpard) ⌘1 thru ⌘9 do not work upon initial Safari launch. I must first access the shortcut via the Menu. Then things work normally. Well, for an indeterminate amount of time (usually an hour or two). After that, I must (re)access the Menu shortcut again to get the keyboard shortcuts to work.
AFAIK, this keyboard-shortcut issue is only with Safari.
The Apple forums also much discussion on assorted keyboard problems.
FWIW, my workaround solution was to re assign the shortcuts with
Shortcuts. Works great!