It didn't blow after all these rounds ? Lucky boy in that cf-18 that it din't desintegrate.
At that altitude, there is minimal internal pressure in the balloon, so if you puncture it, all you do is put a tiny hole in the material and it won’t pop like a balloon at ground level would. Helium will leak out, but very very slowly and it can take days for the balloon to drift down to earth.
To bring such balloons down quickly, you need an explosion to rip a huge tear in it so it looses structural integrity. For that, you need a missile, which opens up the problem of guidance. Radar won’t work, neither will regular IR. Only mainstream missile guidance that might work is high end imaging infrared (IIR), but those seekers are typically only used on short range AAMs, so you need a fighter with high service ceiling and a top of the range IRAAM to have a go at intercepting the balloon. Also, since radar is suboptimal, you ideally want IRST on your fighter to help it find and guide the missile until it’s own seeker can lock onto the balloon.
The PLAAF had the perfect package in the J10+PL10. I think the USAF sent those F22s to have a crack, but without IRST, they probably couldn’t get a firing solution.