No, you cannot save your Limit Breaks unless you are prepared to only fight with magic or items for the duration. In both cases, you end up using a finite resource (MP or items) while also stalling the limit meter recharge, so its not very useful in general.
Note that many characters need to keep using their limit breaks for each level to unlock an alternate one (e.g. Braver / Cross-Slash). You will be better off to use limit breaks asap to progress in the unlocking and have more options.
If you know there is a boss battle coming up then it may be worth fighting with magic or items for a short while (so that you start boss fight with multiple charged limit breaks). Keep in mind that the level 1 breaks charge up really fast, while level 3 or 4 is far slower - you don't want to stall on level 1 limits when they will be up in a short time anyway.
Re. the menu showing multiple levels for each limit break - these cannot be charged concurrently, you have to select one and then charge it from empty (e.g. for Cloud, you can't charge Meteorain, switch to Cross-Slash for random battles, and then switch back before boss fight expecting meter to be full).