If I validate my implementation(s) of Rijndael against the Advanced Encryption Standard Algorithm Validation System (AESAVS) specified validation testing requirements is it fit for purpose and real world use cases? Can I then state as much? What about other ciphers and their test vectors that lack NIST authority?
Based on my reading of that document, it looks like it only covers Rijndael (aka "AES"). Moreover, I would say that the AESAVS test the correctness of your implementation, but not the security.
From the linked document:
This document specifies the procedures involved in validating implementations of the Advanced Encryption Standard (AES) algorithm in FIPS 197 : Advanced Encryption Standard 1. ... This publication ... includes the specifications for the three categories of tests that make up the AESAVS, i.e., the Known Answer Test (KAT), the Multi-block Message Test (MMT), and the Monte Carlo Test (MCT).
So these tests will show that your implementation produces the correct output for a given input. They do not make any claim about whether your implementation is robust to timing attacks, or power analysis attacks, or really, any kind of attack.
So, as to
is it fit for purpose and real world use cases?
That depends, does your purpose include being secure (in addition to being correct)?