Aerith (27, Cloud (28), Tifa (L27) I am currently maining Aerith but I used Cloud a lot when I was levelling up my Cleansing materia at the arena, he went up a few levels in the process and I also got some other materia levelled up too! (so Aerith is now rocking L3 Fire, Ice, Lightning and Wind materias on her shiny new arcane sceptre, Prayer is nearly L4 too)
Let's see, I try to explore everywhere, I backtrack a lot including to see if I missed things or after some time has passed go back to see if it'll let me collect some things it didn't before. I try to soak up the atmospheres to a significant extent, reading the random npc dialogue, after a significant event happens I take a quick lap around to see if any npc dialogue has changed or been added or if notable NPCs (like Johnny's Father) have popped up, if they have I'll have another quick look for them again later to see if they went somewhere else. I did random things like seeing if I could take Aerith back to the church or the park (I could but for the latter, she wouldn't use the tire hop or the slides like Cloud or try the swings =-( ), and enjoyed having her around, soaking up the music sometimes, vibing by the joke box watching her and Cloud dance. I relished the brief times I was in control of Aerith, like when she was in her red dress, I went to see where it would let me explore with her (not very far) and note the NPCs particularly the Poet, and I explored Corneo's house with her and found treasures (Fury Ring) When I was Aerith in Madam M's parlour I pressed Triangle at certain objects and got scolded by Madam M, it was funny and when I was controlling Cloud and both he and Aerith were in there dresses I went for another trip around town (I found Sam and Madam M and got a cutscene conversation this way) , and the Poet had new dialogue too.
I had way too much fun in Chapter 9, I love it and C8 a lot. I'm having way too much fun in general. Did you know you can kick and shift the bandits around the screen at the campsite when they are lying on the ground or barge into the NPCs and knock them off balance?