I agree with what has already been said here. I would NOT recommend The Creek for a new trad leader, and most certainly not in the hottest month of the year. It can be done but be ready to be humbled and stay safe. If you are going there anyway here is my advice:
1) Remember that few people come to The Creek to climb less than 5.10. That means easier routes outside of the popular cliffs see little traffic and non-existent hardware upgrades. Make sure you can see the anchors or at least verify on this site that they aren't old rusty pins with sun-baked tat.
2) Avoid long routes (>100'). These can turn into mini-epics quickly just trying to get to the anchors given a small rack and a lack of endurance on cracks.
3) Stay away from the Friction Slab. Those routes have antique anchors that are incredibly sketchy, and a lot of the holds have eroded away making them several # grades harder.
4) 5.9/5.9+ is a really mis-leading grade at The Creek (although with trad where isn't it). It can be anywhere from 5.7+ to 5.10+.
5) The biggest problem with <.10- is route density. Yeah, maybe 6 routes are listed on a cliff easier than .10-, but one is a choss slog, one is offwidth and requires 4x #6s, one is 110' and you don't have 9x #2's, and one is only 5.9 if you have the hands of a 12-yr old girl (looking at you Chocolate Corner). So you end up with one to three routes on a cliff that are actually in your range. If you want to do more than 3 routes in a day you're looking at hitting at least two different cliffs.