Is it legal to install a individual circuit such as a 240v 30a and put in 2 receptacles instead of one, if the loads would not be used at the same time?

What you want to do looks code compliant per 210-21 and 210-23.

I know of nothing that says a 240v 30a ckt can only have one outlet. In a residence we normally only put one but that's because we need only one.