1: Very important. A healer can easily do over half as much damage as a dedicated DPS, so adding their damage goes a long way towards making fights take longer, and ultimately making your job of keeping people alive easier (Mobs dying faster means less chances for mistakes, less chances for tank cooldowns to run out during trash pulls, etc.)

2: Outside of the stuns mentioned earlier, no. Sadly healer is the most basic of roles, the devs appear to have assumed that since keeping people alive is so important, healers need as few outside distractions as possible.

3: No.

4: /pac is just for the actions available on the pet hotbar, like Place and Heel. The only way to get your fairies to use their abilities like Whispering Dawn is to use your own version that tells them to do so.

5: Do what you can to simplify names, and turn on the hotbars over your party's names when they've taken damage. You can't just keep your eyes glued to the party list, you have to keep your eyes on the battlefield and especially on the boss to manage mechanics. You should try glancing at the party list every so often to make sure minor damage isn't wearing people down, but primarily keep your eyes on the monsters to get an idea of when to heal: If they do an attack that looks big and beefy, probably a tankbuster or AoE.

6: Focus target the boss. You already have easy access to your tank's HP, it'll always be the second (Or maybe third in 8-person trials/raids) person in your party list. Focus targeting the boss provides an easier way to see attacks the boss may be using.

7: No. The spell you should EVER make macros for is raise, and that's to add a simple line in party chat letting the other healer know who you're raising. As mentioned before, macros cannot be queued. Queuing is a system where you can use an ability shortly before your GCD is up, and it will be "queued" to go off as soon as your GCD is available. If you try to fire a macro off just a split second too early, it simply won't go off at all, and so you'll need to wait until the GCD is clearly up before hitting the button... it's far better to conventionally target the character first and use the action normally.

8: Healers are very important in PvP. I haven't done a ton of it, but I've generally found that as a healer you'll want to stay behind the melee and tanks so anyone who wishes to rush you will have to run past all your allies to reach you, while still being in range of the front lines to heal them. Do note that it will likely be fairly frustrating as melee DPS are somehow oblivious to the fact that heals do, in fact, have a range limit on them. Running off after someone plunging deep into enemy lines is a good way to get yourself killed.

9A: Ok, first off the most important thing ever: Your abilities (The actions with recast timers to them) are not for emergencies. Learn them, love them, use them. You can theoretically get through content without them, but they're powerful, do not cost MP, and go a long way towards allowing you to DPS your heart out. You could just DPS for a bit, spend a GCD casting a heal, DPS for a bit more, drop another GCD on healing... or you could weave your abilities between two DPS spells (Ideally after Ruin 2 or Bio) and spend ALL your GCDs on beating a monster's face in while keeping your allies healthy. Your longest cooldown is 3 minutes, which means it can still be used multiple times during a dungeon or trial. If you save them for an emergency, anything that feels like a proper "emergency" probably can't be resolved with those anyway, and if you find times where they'd be useful earlier, that can likely avoid an emergency situation down the road. Perhaps a better way to think of it is that you can keep a party alive using just your abilities most of the time: It is your healing SPELLS that should be broken out during an emergency.

9B: Next up, try to reduce how much you overheal. People don't need to be kept at 100% all the time, and a regen on someone who's already full or a shield on someone who won't take damage anytime soon are both wasted resources. Try to get a feel for how much each of your heals recovers, and try to just heal when people are below that threshold. You can let Whispering Dawn or even just your fairy's Embrace gradually heal up DPS who shouldn't take damage any time soon. Use your healing abilities wisely, and you'll find they can carry you far further than you originally thought.

9C: This relates a bit to the earlier points on macros: Get used to playing one step ahead... or alternatively, be coolheaded enough to be ok with putting things off for later. You generally shouldn't need to react to something that surprises you, and should have plenty of time to switch targets and queue up your next spell while you are casting your current one. For example, say I'm casting Ruin on a boss. I see that it's using an ability with a large cast time and looks like it's steadying itself for a big attack. When I see the cast bar is getting near the end that I won't get another spell off before it finishes, I target the tank while my last Ruin cast is still going, and queue up Adloquium. By playing in this fashion, I have over 2 seconds to change my target, and the tank actually winds up healed from the tankbuster faster than if I had reacted to their health dropping. This is just one example, but in general while you are casting one spell, you can use that time to assess the battlefield and decide "Ok, what will I do next spell?" This is a skill that will take practice to learn, but it will be your greatest asset.