No...
When you install LP9 it will either upgrade/replace.install anything new included with LP9 while leaving alone anything previously installed by LP8....
So don't delete anything... Just let the LP9 installer do it's thing....
Note: Once LP9 is installed.... assuming you are using the DVD Logic Studio 2.0 version and not the app store version... and before reunning LP9 the first time.. Update LP9 to 9.1.5 and update Snow Leopard to 10.6.8 to get the most stable/efficient OS X and Logic Combo that several of us here, are still using...
The Logic Pro 9.1.5 update can be found here...
Logic Pro 9.1.1 through 9.1.6 updates
You can also update LP9 to 9.1.8 if you so wish and is essential if you are also intending to update OS X beyond Snow Leopard........ though personally I'd stick to 9.1.5 with Snow Leopard....
The link for that upgrade is found here...
Logic Pro 9.1.8