I have a large vector image I've drawn in adobe illustrator that at some point needs to be printed on a separate machine without access to illustrator. If I shrink the image to decrease file size for upload then export the image as a PDF can it be scaled at the receiving end again via printer settings and still maintain quality if enlarged?
Illustrator exports vectors inside a PDF as vector, unless you rasterized them first. Vector files are infinitely rescalable, either in print, or when viewing on screen with suitable image viewing software.
Shrinking a vector image's physical size will not reduce the file size of the image.
If there was a printer big enough, you could print a vector image the size of the Empire State Building, and it would still look tack sharp. Vectors do not contain pixels, therefore there is no degradation when making them larger.
A vector AI file saved to PDF is pretty much the same. Everything remains in vector shapes, which means you can scale it up or down without losing any quality.
Resolution and image quality is only a concern if working with raster formats (PSD, TIF, JPG, PNG, etc).