If you mean FlashPlayer:
No, Flashplayer is NOT safe. Every day the holes are more. It is old hat. Almost everybody is using html5 in websites.
I have already since a long time uninstalled it.
When I see the message "missing plugin" , I will set Safari to Safari 8.1 iPad. and in 99% of the cases that will play the video.
(The iPad Safari does not have Flashplayer possibility at all as plugin).
You can do this as follows: in Safari Preferences, go to the "Advaced" tab, check the "show Develop menu in the Safari menu", then go to Safari menu, choose "Develop", choose "User Agents", there choose" Safari 8.1 iPad".
That will do the trick.
Lex
If you must play Flashplayer do as Mike Sombrio says and keep using ClickToFlash. This gives a little safety.
Lex