We would be riding through lots of gravel and creeks and she is very tender footed.
Can't comment on the crack, without at least seeing pics of it. Likewise can't comment on the trim or such, but conventional rims without extras provide no protection to a 'tender footed' horse, so yes, hoof boots sound like a good move - & a healthier one too IMO.
They both told me to pull her shoe and keep her in an boot, while applying dressing.
Don't agree to hoof dressing. Topical goops don't effect the health of the hoof positively & can often be more detrimental. If the crack has infection in it for eg - which it's unlikely not to - putting dressing on can effectively just enhance the environment for growing more of the anaerobic bugs.
As said, it seems boots are a good move, but probably not necessary with regard to the crack specifically. Keeping the hooves frequently & well trimmed, to ensure the mechanics are good & not contributing to stress on the area, cleaning out(may mean 'resecting') the crack of infected tissue and treating it by soaking or such are important measures for growing out cracks.
First, What are an easyboot, that can withstand, high creeks with an current, and deep mud, without coming off, plus I canít afford a lot being an broke college student. My dad normally provides everything for my horse, but I donít see him willing to buy boots for her.
With so little riding & considerations of deep mud, I'd go for a high profile one, of which the new Trails have become very popular. They're also a cheaper boot. While I understand money issues, I don't get that your dad is willing to pay for shoes but not boots. Shoes, having to be replaced 6-weekly are generally the more expensive option, unless you can do the job yourself or have a friendly farrier in your pocket.
Boot needs on the bad foot at all times, and would need to withstand about 8 miles of riding a week.
They shouldn't need to be on 'at all times' & if the horse is seriously lame(then I wouldn't be riding anyway) without protection, IMO riding boots, particularly the high profile ones are unsuitable for this. Easycare & others make a good 'Therapy boot' which is suitable for 24/7 use on rehab cases.
Secondly, Do I need to pull both front, and get two boots, or can I get away with pulling only the bad one and keeping an boot on it.
As you've already said the horse is tender footed, yes, she needs protection for both feet. Either boots, or if you're going to keep her shod, pads under the shoes, or pour-in pads such as are made by Vettec. As infection is a big part of the problem with cracks and as frequent care is often necessary to treat them, I wouldn't be inclined to lock her feet into anything for 6 weeks at a time.
Third, This crack runs kind of by the heel and then towards her toes, but is only bout 1 inch long.
Oh, missed that bit when first read & was imagining a vertical crack. That sounds like it was likely due to an abscess that burst on the coronet band and has been growing out. Wouldn't worry about it overly, but keep the feet well maintained, so when it nears the bottom it's less likely to rip off badly & take a huge chunk of wall with it.