Yes! It's actually pretty standard for amateur golfers to start off with yellow golf balls when they're just starting to work on their golf game. (You can buy some yellow golf balls on Amazon, for example!)
As for Fred? Per CNN Sports, the golf legend said, "I’m going to try and compete. I can’t compete with Viktor Hovland or Jon Rahm or anybody, but I can compete with myself, and that’s really why I come. That’s what I like to do, is make the cut here at an older age."