Are you logged into iCloud on all those devices?
To delete the password
Go to your Mac, Open Safari - Select the Safari Tab at the top, preferences, then passwords, find UKP, and select remove
One of the good thing about mac's, but not so good if you're trying to be secretive. I'm single so have no problem, but even then, if I'm going to be around family/friends, and there is any chance my macbook may be picked up, or used to stream movies or anything, I make sure I reset my safari beforehand (which you could also do, but if others are using it they may wonder why someone has deleted everything and arouse even more suspicion)