The West hoped that Hitler would attack the Soviet Union?

That would mean the West hoped that Hitler would attack Poland as that was the only possible way that Hitler could even get to the Soviet Union at the time the pact was negotiated.

The Soviet Union wanted to modernize and expand. Hitler gave them that opportunity. If anything, it was the Soviet Union that hoped that Hitler and Western Europe would duke it out thereby weakening all their enemies.

Pragmatically, every party knew the massacre was about to start and tried to duke it out.

Smart move on part of whom, Germany or USSR?

Not only a smart move but also quite typical for that time. Note that Pilsudski was a kind of dictator and the Polish government was rather aggressive with respect to all its neighbors. Therefore, the war between Germany and Poland was a collision of two dictators - Hitler and Pilsudski.

You can't be serious comparing Pilsudski to Hitler. Poland had very good historical reasons for having an aggressive stance toward her neighbors, since it was still within living memory that their neighbors had carved them up and made them disappear from the maps. It happened again shortly after this, along with both the Nazis and Soviets committing gratuitous atrocities during their respective genocides.

I would go so far as to say that it is completely rational for Poland to doubt the intentions of Germany, Austria, Hungary, and Russia to this day.

Do not forget Poland itself was aggresor occupying part of already independent neighbour Lithuania some 20years before WW2.

Well, after losing in the Great War, Germany, too, "had very good historical reasons for having an aggressive stance toward her neighbors." Which is the reason Hitler came to power in the first place.