Embarrasing Fact: Power suit made by lowest bidder
Can't do it. Not like that. If you attempt to wall jump off of that pillar, the top block will be detected first by the wall jump. In this case, that's the missile. If you try to go lower, you'll dip into the water and just sink.
The wall-jump followed by diagonal-bomb jump itself is possible, though, but you can't do it without picking up the missiles. It's technically the fastest method, but it's somewhat harder than two diagonal-bomb jumps; you need near perfect positioning with both the wall jump and laying the bomb. With practice, though, it's a viable method. The bomb should be placed much higher, though. Actually, the tip of your blue line in the pic looks almost perfect. Maybe a few pixels right and up. Hit the bomb for max speed (be holding right as the bomb explodes), then unmorph when you've fallen back down to that same height - that actually gets you a bit more distance. Oddly, the hardest part is getting a good wall jump for the bomb jump. Often, you'll jump too low or too close to the pillar.
Aside from all that, it's possible (but incredibly difficult) to just horizontal bomb jump over the entire lake.
It's all moot, though, since there's no reason why skipping the missiles will give you a lower percent; you need them to beat MB's first phase.
And if you're talking about using the space/time beam to beat the game... that isn't a valid way of winning. And you'll also have to horizontal bomb jump over the entire room to the Chozo Statue for the Gravity Suit. You also would have 10%: Morph, bombs, missile, super missile, power bomb(both entrances to the main part of Maridia require it), Gravity Suit(Get out of Draygon's room), Charge(kill Botwoon, 5 supers and 5 missiles isn't enough), Ice, Spazer, Plasma.
Just recapping what Kej said earlier, but even with 5 PBs it's not enough to kill Ridley without charge beam (don't remember if PB hurts Botwoon). In addition, that shortage of missiles won't get you past MB's first phase, where you have to break through the glass and hurt her enough.
Kejardon: Do you still have a copy of your updated 14/15% faq around? I misplaced the file, and the one on GFaqs is outdated, I think?
You can kill any boss with charge beam or not. Every boss reproduces at least one thing that can be destroyed and it will most likely give you at more missiles.
Embarrasing Fact: Power suit made by lowest bidder
"You can kill any boss with charge beam or not." Absolutely false. Botwoon has no projectiles you can kill for pickups. Neither does Ridley or all of MB's phases, but you don't need to kill them for a space/time run. This ruined one of my earliest attempts at a low percent when I entered the room with Zebetites armed with 5 missiles and 5 super missiles, and last saved in the room just before. >_< And you'll also need ice beam to reach Draygon, and to trigger the space/time beam. Spazer/Plasma alone is a guaranteed crash.
That said, there is a way to get only 8%, but it's even more illegitimate: Pick up a ton of missiles to kill Botwoon and skip the charge beam, then use the reset glitch to get rid of them, *then* use the space/time beam to end the game early.
Purple Lizard: The one on GameFAQs is the latest *finished* version... I meant to update it but got sidetracked with Ridley again. >_< I have a semi-updated version online right now, but there's still a bunch of stuff I need to finish. http://www.metroid2002.com/kejardon/Documents/super_metroid_15.txt I've figured out all the additional information for Ridley I wanted, I just never got around to updating it. And the spelling... well. I procrastinate naturally when it comes to English. ;)
No, really I dont know how, but im sure that i see some pickups, maybe cause Im playing Pal. But I only see it one time , because I thought too, that ridley doesnt drop Items.