Why were the rulers of Thamilagam during the 8th and 9th centuries C.E unaware of Sri Sankaracharya?

Proponents of the 788 C.E theory need to explain why the rulers of Tamilnadu, Andhrapradesh, Karnataka, and Kerala between the 8th and 9th centuries CE, who supported different faiths, had no connection with Sri Sankaracharya, despite His reported extensive travels during that time. It is surprising that they did not recognize His presence, and there is no record of Him in contemporary literature.