EAA sells them, and I think Brownell's still sell them.
There are two types of safeties for the clones.
One type, usually used on the P9 uses a shallow recess on the left side of the frame, and a tiny spring-loaded flat plate that's pointed on the end which is retained by the left side safety. This fits into the recess on the frame, and gives the safety it's "click"
The second, (new style) safety has a lobed hole completely through the left side of the frame, and a spring-loaded plunger inside the safety that fits inside the hole and gives the "click".
This type is easy to recognize by retracting the slide and looking inside the frame on the left. You can see the hole and the plunger.
This safety is the one that's notorious for being "mushy" and requiring a fix.
Your P9 probably uses the "old" style.