Question: So I have heard that using QuickTime plugin has its advantages in the Safari browser, but how does one safely install it?
Answer: If you are already using Safari 8 browser (which comes pre-installed with OS X Yosemite), you have QuickTime plugin installed by default.
This will force QuickTime to run in the background and it will be available whenever required. For example, if the video fails to load in Safari browser and your second preference is QuickTime, then the video will load in the QuickTime player.
Remember: You can also select “block” if you want to disable QuickTime plugin in Safari.