Joshua 7 — It almost seems like they dealt harshly with Achan, but in reality, it was either deal with him and get rid of the things that were devoted to destruction, or have destruction brought on all of Israel. When God says something, he means it. I also like the NRSV/ESV translation of מעל as “broke faith” since it reminds me of breaking covenant, which is essentially what was done in taking the devoted things into Israel’s camp after being commanded not to.
Joshua 8 — Nothing much to comment on here. I do wonder how long it took Joshua to read the entire law of Moses to the people. I have to imagine that it took quite a while.
Joshua 9 — The Gibeonites were pretty crafty. I get that the Israelites swore an oath to them not to kill them, but it was under false pretenses, and one would think that the original command from God to wipe out the inhabitants would have superseded this oath. On the other hand, I’ve read scholars who think that Joshua was written to explain the presence of foreigners in the promised land in Israel’s later history. So if that’s true I guess the author would have to come up with some ways to leave inhabitants alive in the narrative. I don’t know that I buy that, but anything’s possible I suppose.