Is the bottom G (flat) in the left hand a tie or a slur? As in, do I need to play it on tick 7/9 in the bar or not? If yes, what does the notation signify?
This is one of the many instances in piano notation where musical intention is conveyed rather than strictly practical technique instructions. The effect required is of one voice holding the Gb throughout the bar, another performing the arpeggio.
So how do we achieve this? Consider how using the sustain pedal will affect it. I don't think anyone would play this bar WITHOUT pedal? So what' we're really being told is to give the first Gb a little more weight so that it sounds as if it's sustaining more than the (lighter) arpeggio notes. Or you might use the middle (sostemuto) pedal - if your piano has one - to sustain JUST the first note of each bar. Several ways of achieving the notated musical effect.
There is no way to notate a 9/8th note without tie and it copies the note in the treble. The note in the treble additionally has a phrasing slur so chances are this is a tie at least conceptually.
However, at least in the left hand it doesn't really matter in execution on a piano since you need to restrike the key anyway at that time for the upper phrase in the left hand.