Can hypersonic aircraft be agile without the G forces harming the pilot?
Well, 2 G's is 2 G's, regardless of what speed you're flying.  A level (coordinated) turn with 60 degrees of bank is 2 G's, regardless of your airspeed.  What changes is your turn rate and turn radius; at 20 knots, a model plane at 60 degrees bank can probably complete a 360 degree turn in a few seconds and a radius of maybe 10 yards.  At 300 knots and 60 degrees bank, a conventional jet will need a minute or two and a turn radius of probably a couple of miles.  At 2000 knots and 60 degrees bank, an SR-71 might overfly a few states making that same 360!  But it's all 2 G's for each of those aircraft.

Now if you want the SR-71 or some similar highly supersonic aircraft to have the turn rate &amp; turn radius of your 300-knot Lear jet, then you'll get a LOT more G's -- which can induce various other issues with your supersonic beast.  And if you want either of those to keep their speed while turning in the radius of your 20-knot drone... well, let's just say that you're talking about G forces beyond the realm of all human experience to make that happen!

There are all kinds of discussions that can be had about how hypersonic aircraft can be made more maneuverable without doing things that risk losing control, flaming out the engines, creating unacceptable amounts of drag, and so on, but all of those discussions take place in the context that high speed + high turn rate = more G's, and given any 2 of those factors that you choose (i.e. how fast you want to go &amp; how much G-loading you're willing to sustain), the third is determined.

The max G-loading for a human is pretty well about 9 G's, so pick whatever combination of the other two factors you want.  Or go unmanned -- which with today's technology is probably cheaper.