Fighting GutsMan with the Buster only takes too long though. BombMan doesn't even want to deal with you, so you get his weapon almost right away. But it doesn't matter just so long as you get the Magnet Beam before IceMan's stage.
IMHO fighting GutsMan buster-only is a lot more convenient. Hyper Bomb's delay just makes it feel cumbersome, although it's certainly not as bad as Crash Bomb, given how little Guts Man actually moves.
I take the same order as Vix. But I must say, ruling out pause physics abuse (something I consider cheap, hence my general distaste for 9's time attacks) 1's fortress bosses are damn evil. That's what makes it the hardest of the series to me.
MMPU took an interesting route with that. The fortress bosses are pretty watered down, to say nothing of the stage layouts. But the RM rematches...hell. You get the more "modern" 8 teleporter room, except with no recovery, ever. I don't know who thought that up.