A tethered balloon as an observation/recon platform is very plausible at any time starting in the late 1800s (or even earlier with an earlier invention of hot air balloons!)...just need someone to think of it. Very practical, too. You could see the whole enemy line of battle and direct your fleets accordingly. Recall that without modern propane burners you need to "Fill" the balloon with heat from a large fire (on a wood-and-sail ship!) and can maintain a little bit of lift with oil lamps, which works well for tethered balloons but won't allow for self-mobile balloons.
Bombing from balloons is highly risky for little gain. A field gun could shoot you down (huge target that has to slowly float over your lines...winds permitting). Frankly, a line of artillery will be far more dangerous to the enemy.
Gliders...need something to get them high enough to work, otherwise you simply glide a hundred meters off the deck and into the ocean. Even balloon-launched means splashdown, only this time say a couple kms away from rescue now. You'd need airplanes to make gliders realistic, which of course also makes them obsolete for most uses.

Not a practical solution at all.
Kites...I can't really think of any practical use there at all. Too subject to the whims of the winds to put people up there or try to direct munitions drops. The latter also is far less practical with far less range than a simple cannon. You'd need a line hundreds of feet long to equal cannon ranges...and then you have to control it that far away to get it over the target and manipulate whatever mechanism drops the munitions (difficulty increasing greatly with each foot of string).
In summary: Tethered Balloons for observation: yes, anytime, really, and very practical...genius even. Gliders or Kites: no, totally impractical. Bombers of any platform: no, impractical, cannons work far better in about any circumstance.