The Crop option in the Format tab comes into play when an image/photo is in the document.
The Excel document in your page is an object and the Crop option isn’t seen.
To get round this, right click in the Quick access Toolbar (QAT) > Customize Quick Access Toolbar > Choose commands from > All commands > Scroll down to Crop Picture/Crop Tools > select one > Add > OK.

Now, when the excel object is clicked and the ‘handles’ are showing, you can click the newly created Crop Picture/Crop Tools shortcut and opt to crop and crop as desired.
Click the image below to see a short video of how it’s done.