Why do we use को instead of पर or में?
Well, को is just the default postposition used with days and dates. में is used when talking about longer periods of time (मार्च में, गर्मी में, इक्कीसवीं सदी में (in the 21st century), etc.). पर is simply not used with adverbs of time.
Can we use
Julia goes the home on Wednesday.
No that is not grammatically correct.
"Julia goes on Wednesdays home" should also be correct... हो न?
No, this isn't correct English.