Good questions with great dialogue! To clarify, the sequence Carrie has written for the science is the preferred sequence.

So, between the 2 choices being discussed here, for 8th grade, doing physical science with Exploration Education would first be recommended. For 9th grade, doing IPC would be recommended. However, for whatever reasons (personal preferences, international/national standards, future plans, previous credits earned, etc.), families sometimes want a strictly Physical Science course for high school. If the desire/need is to complete a strictly Physical Science course for 9th grade, Revival to Revolution's Advanced EE option fits the need nicely.

In speaking with Carrie about calling the IPC course a Physical Science credit on a transcript, we discussed that the proper title for the WG IPC course really is Integrated Physics and Chemistry, which is a commonly used title for science courses in high school. It is a more difficult course than a physical science because of the chemistry component that is added, and it is the preferred title for the science credit earned in WG.
As far as whether the Revival to Revolution Teacher's Guide is needed for the plans, we are assuming students completing the science in Revival to Revolution are also using the Inventor Study, as it adds more depth to the credit and maintains the Charlotte Mason aspect of learning within the subject of science - which HOD users tend to want to do.

Carrie's Inventor Study plans include the pages to be read each day from the Inventor Study resources, the ebb and flow intended between The Story of Inventions and the biographies of inventors, directions for how to complete the notebooking entries in the Inventor Student Notebook, assigned questions from The Story of Inventions to be included in narrations, and pacing that is balanced alongside completing the EE Study. For these reasons, it is important to use the teacher's guide. I hope this helps as you determine what you would like to do for science this upcoming year! If it is for 8th grade, and it sounds like it is from the last post, EE with the Inventor Study alongside the RevtoRev plans would be the the preferred option, and I think you'd thoroughly enjoy it! Have a good weekend, ladies!
In Christ,
Julie