This article – https://futurism.com/spacex-blow-falcon-9-rocket-launch/amp – states that after 88 seconds, the first stage engines will shut down, and an automated abort command will be sent to the Crew Dragon Capsule.
It states engineers hope the Falcon 9 will explode mid-air.
Why do they think it will explode after engine shut down? Why does this not sound certain? If they do want it to explode, can they not fit a small explosive charge to make certain it does?