Seeking the Origin of the name you'll always get two meanings for Bodo. In Old-Saxonian: Leader. In Old High German: Messenger. Even if old saxonian is older than Old High German both meanings are co-existing with the same justification: the both meanings can be allocated in indoeuropean "b(h)eudh-", which is Bodo's parent.
A Messenger (15th century)
First of all "Bodo" appeared as expression between germanic (600 b.c. -500 a.d.) stem "biotan" (which means to offer) and Old Saxonian (about Year 0). So, the question is: when did it became a name?
As a name "Bodo" first apperas in the name of Marbod (Source: ancestry.org), king of the marcomanni, a german tribe.
so that it can be traced at least 2000 years! Marbod is typical for the construction of a german first name. Usually it has two parts with different meanings. In case of marbod: Mar stands for market and bod for messenger. Must have been an older name even back then because for naming a royal it must have lost the connection and popularity of it's original meaning. (Or can you imagine a king telling you the news from the market?).
First official indications on Existence of the german language can be found much later. In a latin report from 786 is a hint about a mass that was held in "theodiscus" (german), the language of the
Informations about Old High German (in german)
"Dat gafregin ih mit firahim firiuuizzo meista · Dat ero ni
uuas noh ufhimil · noh paum noh pereg ni uuas · ni nohheinig
noh sunna ni stein · noh mano ni liuhta · noh der mareo seo ·
Do dar niuuiht ni uuas enteo ni uuenteo · enti do uuas der eino
almahtico cot manno miltisto ·"