Yes, this will work. Just remember that you can’t use both PRE and POST effects at the same time because an algorithm on the H9 can either be run in PRE or POST, but not both.
For optimum performance, since you’re using a loop switcher, it’s best to take the H9 out of the loop in instances where it is not being used. For instance, if the algorithm on the H9 is running in PRE, make the loop switcher take the H9 out of the effects loop. If it’s running POST, have the loop switcher close the “pre” loop.