The other answers have captured the essence of the process very well, so I'll try not to repeat. In the earlier stages you are more likely come come across chords such as you have asked about and they may have some more common, 'first look' scales that apply. I'll just address those you have mentioned here -
G7#9#5 - This is an altered dominant chord, it's close to a dominant chord suggesting a diminished scale. One diminished scale, the whole/half, doesn't have a major 3rd, so doesn't fit. The common diminished scale that fits over a dominant chord is the half/whole diminished scale. However, this scale doesn't have a #5, so the chord spelling can't be suggesting that. The commonly used scale for this chord is the 7th mode of the melodic minor scale, the Altered scale. It is spelled 1, b2(b9), b3(#9), 3, b5, #5, b7. I've renamed the intervals to reflect how it is commonly though of, strictly though the scale is spelled 1, b2, b3, b4, b5, b6, b7.
E7#9 - Without the 5th being specified as sharp or flat you are a bit more free, and the common choices are again the altered scale or the half/whole diminished scale. This involves altering the 5th but it's not that strong a tone in this idiom and can generally be pushed or pulled where necessary.
Dm7b5 - Is usually seen as the ii in a minor ii V i. It is generally played as the Locrian scale. Commonly however a player may use the 6th mode of the melodic minor, the Locrian nat2 scale. This scale is spelled 1, 2, b3, 4, b5, b6, b7. If this scale choice works it can sound really good, but if the natural 2 sounds awkward then the standard Locrian scale should work fine.
C9 - By default is Mixolydian.
Db9#11 - Is a Lydian dominant chord, the 4th mode of the melodic minor scale, it's scale is spelled 1, 2, 3, #4, 5, 6, b7.
All the above are 'defaults' for playing jazz in this idiom, play around with them and see what you get, but they are far from strict rules. It's up to you to choose the scales you like the sound of, and the magic little shifts of harmony, or feel, that you hear the greats make (in this idiom, think Herbie, Shorter etc.) are often when they pick one scale the first time around, then pick another the second. Or even create some tension in a minor ii V i by playing Locrian nat2 at first, settling it down to plain Locrian then moving on, or vice versa.
You can play any scale over each chord, aiming to satisfy the chord tones. Once you are comfortable with the 'defaults' suggested above then try different scales that satisfy the chord tones or even try scales that diverge from the chord tones somewhat. For example playing the D altered scale over D9 for a measure before running down in D Lydian dominant and then finishing off with the D7 chord tones, or a D mixolydian. These sideways shifts are the hallmark of the idiom and can make for very free improv, though it can be a little overwhelming at first.
There are some general starting points, the 1, 3, 5, 7 will tell you wether it's maj7, min7, dom7 or minMaj7. The upper extensions will narrow down the pool of available 'first choice' scales, and generally most alterations will be on dominant chords. On these a #5 indicates Altered Scale, a #4 indicates a Lydian Dominant scale and a #9 or b9 indicates half/whole diminished or altered. However this is not set-in-stone and a 7#5 chord may well work best simply as a Mixolydian with the 5th sharpened.
The chord spelling is usually suggesting roughly what the composer intended eg, E7#9#5 = Altered, E7#5 = Mixolydian with a sharp 5. However this can be heavily lost in translation with the realbook leadsheets, but that shouldn't be a major hinderance. To properly learn a jazz tune you should be taking into account what the melody is doing, what sounds best to you and how you have extended the previous and following chords, all in order to make your own decisions on what scale you will use. When you hear musicians seemingly leaving the written changes altogether but still sounding coherent they are essentially embarking on journeys encouraged at first by small alterations of the suggested chord/scale and then going from there (if we think of this as THIS, then think of that as THIS then we can get to a completely different key, coherently..)
In truth any chord sequence that lends itself to modal playing can be navigated in many many ways. A good one to start with is Havona by Weather Report. It's just 4 Major chords, all leaning toward Lydian, you can start by playing the Lydian scale on each, then see if the natural 4 works on any of them, then see if you can think of chord 2 as a mode of chord 1, then see if you can think of all of them as modes of each other with steps up or down. There is no right answer for this tune, like all modal playing, and it's a relatively easy playground on which to experiment.. (Just slow it down, at the original speed it's a little frantic!).