Can you upload contacts from a car [Kia] *to* an iPhone?
Unfortunately, it's highly unlikely that you will be able to send contacts back to your phone.

While the iPhone (iPhone 4 and newer) supports the Bluetooth Phone Book Access Profile (PBAP) the process is typically only one-way.

There are two roles in the PBAP profile:


Phone Book Server Equipment (PSE) role - this role is for the device that contains the source phone-book objects; for example, a mobile phone.
Phone Book Client Equipment (PCE) role - this role is for the device that retrieves phone-book objects from the PSE device; for example, a portable navigation device (PND).


Your iPhone acts as the server and the car radio acts as the client.  


  Phone Book Download Feature
  
  This feature is used to download the entire content of a phone book
  object. It is especially designed for devices with relatively large
  storage capacity that are typically attempting to download and locally
  store the entire phone book.
  
  Note that this feature is very basic. In particular, phone book
  entries are delivered in ascending index order only. No sorting is
  possible.



M = mandatory

In the Bluetooth specification for Phone Book Access Profile (where the above info was sourced), there is no "push" function; only "pull."  This means for your iPhone to receive the Phone Book, it must change roles to being a client and your car radio to becoming a server.  I can't find any documentation that indicates iPhone supports this role or the Kia radios becoming a server.