Sorry for the slight spoilers for a 50 year old short story below:

Larry Niven's "The Hole Man" dealt with a weaponized black hole, much as described in this article.

I also imagined this was going to be about keeping black holes just above the evaporation mass, and then starving them out before launching them at a target, so they "detonate" right as they arrive.

Is it really true that nothing would change if the Sun's mass was suddenly compacted by several orders of magnitude (into a point mass or black hole)?

This seems unintuitive to me. The sun is a million miles in diameter, so surely shrinking that to zero would lower the amount of gravitational force infinitesimally since the gravity is 1/distance^2 not linear. I would think the planets would sort of drift ever so slightly farther.