I think from what i've read while researching these springs http://www.extremepsi.com/store/product.php?productid=22141&cat=0&page=1 would be enough to run HKS 272's to 9k, but if I decide to run the HKS 280's to 9k I'd need beehive or dual spring setup. Is this true or am I missing something?

If you plan to upgrade to more aggresive cams then I recommend you just get dual springs now. Id go with kiggly for springs. This saves you from wasting money and buying springs twice.

Kiggleys would be a better choice for the 272's. If your end goal is to use larger cams then the Manley duals would be best.

The single Manleys in the link you posted are good for very mild builds with lower RPM and smaller cams. They don't have enough spring rate to control the valves (especially heavy valves) and prevent float, bounce, etc.

Like others if you plan on upgrading later then go with the Kiggly beehives. They can handle any rpm.
Here is the spring setup, he also sells a street version that use steel retainers.
http://kiggly-racing.com/all/beehive-valvesprings-4g63.html
Here is some info about his springs and where he talks about them
http://kiggly-racing.com/valvesprings_tech

If you are looking to make power upwards of 9k rpm, you're definitely going to want to consider Kiggly beehives and his HLA.. among a host of other things. Skip straight to building for the higher rpm power band if that is a for certain plan.

There are a great many bits of prep along the way that will benefit any build, it's more cost efficient not upgrading things twice and the "penalties" for running a bigger cam/turbo/SMIM combo before taking full advantage of them are near non-existent. Typically played up by those who:

1.) Have never had such a setup
2.) Can't adapt to how to drive different power bands
3.) Lose sleep at night over things like the "lag" they might get going from their T25 to a 16G..

Can't even tell you how many "car guys" over there years and to this day have tried to tell me what's up till we actually go for a ride.