Description text, not footer text... ok... and too late to edit.

You have style classes applied to those sections of text now, and presumably you could style

.style9, .style11, .style12 {font-size: 0.9em}

in your stylesheet. These might not apply to other products' descriptions, however, or they might apply to other elements of the description in other products, so your best bet is to wrap a div around the whole disclaimer - copyright block and give it a class:

<div class="productFinePrint"> text text </div>

and then style that in your stylesheet:

.productFinePrint {font-size: 0.9em;}