Labelling Jazz Chords

Should I, or Should I not, include extensions in the chord symbol if they 
are found in the melody?

For example, in 3/4, I have an upward arpeggio of B-D-A, with the first
two 
notes as 8ths, thus making the A a half note for the remaining two beats.

If this is over a GMaj7 chord, should I put GMaj7, or GMaj9?

Additionally, is there any shortcut notation for a changing bass under a 
sustained chord?

Suppose I have E9 to E9/G# - does anyone write " /G#" just to show the
bass 
motion, or do they typically put E9 E9/G#?

Finally, what's the standard for something like A/G? Is it better to put 
A7/G or will A/G cause people to not voice the 7th in the chord?

TIA,
Steve