Does an iPad Pro 9.7 Smart Cover fit a iPad 9.7 6th generation?

Smart cover, no. Those attach with special magnets the 6th gen does not have.

You can pull up the tech specs for various models

Apple - Support - Technical Specifications

Many ipads share the same chassis so cases will fit multiple models (some easier than others. there are some that are a couple of millimeters thicker or thinner, so tight fitting silicone cases likely will not fit, but more forgiving portfolio ones may

They do have smart covers for the 6th gen

iPad Smart Cover - Pink Sand - Apple

I could be wrong with the magnet placement, although when I look at the compatibility for the 6th gen it doesn’t like the pro.

If you have an apple store nearby you could always take your device in and give it a try.

This seller on Amazon seems to think the iPad Pro 9.7 smart cover fits the 2018 iPad:

https://www.amazon.com/Apple-Smart-Cover-iPad-9-7-inch/dp/B06XS7G71Y/ref=asc_df_B06XS7G71Y/?tag=bingshoppinga-20&linkCode=df0&hvadid={creative}&hvpos={adposition}&hvnetw=o&hvrand={random}&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl={devicemodel}&hvlocint=&hvlocphy=&hvtargid=pla-4584070139426231&psc=1

One advantage of amazon, they hold their retailers to good return policies. So if it doesn’t work they can likely return it. (just make sure the listing doens’t note that it’s as is or anything like that)

I’ve only had to return stuff on amazon a couple of times but have had no issue either time.

I do really well on Amazon. I finally received a Hard Shell Backlit Keyboard Case for my iPad Pro 11, which I've waited a long time for. The thing is simply awesome and it's all aluminum and really well made. And you're right, if something doesn't work for you, just open a return with Amazon and boom, no issue returning something and getting your money back.

A lot of people don't know this, but in December, Amazon and Apple came to a deal and Apple has opened an Apple Store on Amazon.

https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=apple&rh=i%3Aaps%2Ck%3Aapple