SOAS is a really good university, but more options would be open to you if you scored in the high 30s, so a 38 or 39. You could still apply to SOAS as an insurance option. I don't know what course you are applying for, and each will have different entry requirements, but remember that lots will depend on your score in your HL subjects, not just the total point score. So they might want 6,6,6 or 7,6,6 at HL as part of the 38.
Australian unis are good, they offer more degree flexibility than english ones, but places like LSE and UCL are ranked very highly.
It also depends what you want to do and the experience you are looking for. Do you want to be in London?
Maybe I'm biased, but I did the IB and then a gap year, and applied with my results. It was a lot less stressful, and also because you have your grades, you can be certain that you meet entry requirements. It also gives unis something concrete, they know you have achieved the grades.
Your application would be stronger if you applied after a gap year with a point score of 38 than if you apply with a predicted 34.