"is there any good Defence ammo available for the 9x18?". Yep - straight ball is just about the best you can ask for in that caliber, same as with 380, 32 and 25.
Lots of folk, especially the ammo makers who hype this stuff will tell you that nothing other than their 'flying ashtray' hollow points or their 'soft nosed serrated edge small bore boolet that expands to big bore size' is sufficient in these medium or small bore calibers to defend yourself with. The truth is that these slugs rarely move fast enough to expand or carry the energy needed to penetrate deeply enough to bring on incapacitation; and if they do move fast enough the expansion is most likely going to prevent the penetration necessary to stop or slow an assailant.
To anyone who purchases a 22lr, 25acp, 32acp, 380acp or 9mm Mak for defense I say: forget expanding ammo, use plain ball, and practice for multiple shot encounters. Soft tissue targets are the best and this is usually right to the breadbasket, or with ball you can shoot two to the chest, then two more to the chest. These smaller calibers won't 'stop' anything unless the hits cause immediate pain or disability (arm doesn't work, foot took a slug and can't run, can't see, chest hurts) and they need penetration to accomplish that and the only way you get that degree of penetration is with a solid (ball) slug or a hard cast in swc configuration. Hey, even the SAS practices (or at least they did when I knew'm) two to the chest and two to the head and that's with 9mm. JMTCW. Mikey.