You can but we don’t recommend it. The SAT is a 4 hour test which take a lot out of the student both mentally and physically. To add another test on top of that would almost guarantee that you don’t do well on the second one.
Instead, look to take the Subject test around the time you finish the class in that same subject. The test is completely knowledge based so if you just went through the class, the information should be fresh in your mind.