While I don't endorse entering a trade at 0929, opportunities do occur before the NY open. In fact, two of the best trades I've had recently were entered pre-open, one at 0650 and this morning at 0730. Granted they were taken just because I happened to be up and saw them (I don't set my alarm to get up early to trade pre-market), but if you do happen to see something that meets your criteria, there's no reason to let it lie simply because it's before 0930. Today, for example, I was essentially done by the time the market opened. And there are often opportunities presented by the behavior of price around 0830 economic reports.
Therefore, since you are just beginning this phase, I suggest you not get locked into a pattern of avoiding perfectly acceptable trades simply because of the time at which they occur. They can be worth the potential loss of a couple of bucks. If it's important to you to start after 0930, then do so. But remember that Europe is trading at about the times of the trades I referred to above, and they can move price just as well as we can.
As for the bar interval, at some point, if you continue with this, you will realize that the bar interval is largely irrelevant since all charts are tick charts. Today, for example, with the hindsight charts I posted, I showed that the result was essentially the same whether one used a 15m bar or a 5m bar. I don't know how many people will pick up on that, but there it is. How the trades are bundled is purely a matter of convenience. One can, after all, create any bar interval he likes, even with older software. Or he can do without bars entirely and trade a line. This is not to say that if you like a particular bundle, say 5m, that you should not use it. Just don't forget that that 5m bar is nothing more than a personal choice. The market couldn't care less. The market moves in ticks.