I forgot what part of zone 9 you live in. I only know the ones that do well in my Sacramento area zone 9. So where are you?

I'm leaning in a different direction than you are inclining toward so these suggestions may be meaningless for you. I don't think the needle tree will help give the house a sense of being sheltered, but a small tree would. A multi-trunk tree would add a little filter-screening for more of a sense of protection while sitting on the porch. The purpose of a row of shrubs in front of another row of shrubs is lost on me. I'd do shrubs and groundcover, or shrubs and grass. While I'm not a big fan of the lollipop trees, I think it would help if their canopies were enlarged, raised and matched (in the trimming process.) Other notes on the drawing.

Yardvaark- thank you so much for the sketch! I have thought of the tree idea in the island area but I have attached a wider shot of my house with driveway. There are 3 exisiting crepe myrtles lining the drive (not my choice...they were there when we moved in- the purple blossoms are a nightmare in the driveway!!) but I was curious as to your thoughts of if adding an additional tree would be...too much? Too cluttered?

Never thought of the ground cover idea..I love it! Any specific suggestions on what kind?

The included picture is an older pic before we demo'ed the crumbling brick beds and the 2 trees that had an unfornate encounter with an overzealous gardener who trimmed my trees to oblivion. I need them to grow back to look like the below- I agree :)

I think you have a couple of options to take.
You can take advantage that you live in one of the richest horticultural growing areas in the world and have a drop dead gorgeous garden of unique plants in a harmonious layout OR you can go the way of a paint by numbers garden design using tried and true plants that are considered easy care ( boxwood, agapanthus, dietes , yawn, yawn yawn. ) OR you can bump it up a notch and plant a few eye catching horticultural treats mixed with some every day easy care plants that are arranged artfully.

I have an identical house to yours with the addition of a simple picket fence and gate that encloses the front garden ( to keep my dog safely inside).

In the front small bed that borders the porch I planted a queen palm , a bouganvillea and a leucospermum cordifolia as the main characters and have an underplanting of succulents. It is an extremely low maintenance garden area but the seasonal color, textures and forms are always interesting ( one of the reasons it has been published several times by several different magazines and books)

If you are located anywhere near Berkeley try to take a look at a nursery called The Dry Garden - wonderful plant selection . And if you really want your horticultural and garden design socks blown off, check out Flora Grubb nursery in San Francisco. You'll be totally inspired beyond a stick tree, some green groundcover and two loli-pops garnished with boxwood.

That is funny that the lollipops formerly looked closer to what I suggested they become. However, it'll be easy to get them back to size. Just watch that they are carefully shaped as a matching pair.

In spite of the fact that there are crapes at left of drive, I think the house needs to obtain a sense of extended sheltering and cover some of the roof exposure ... which the crapes do not achieve. It could be with another crape, or a different SMALL tree. BTW, the crapes could look a lot better than they do now. Their structure is unmatched and haphazard. If they were mine I would regrow the tops, beginning next spring.

As far as specific type of groundcover, it would be best to get advice from locals. Just keep in mind the specs. you need (height & other characteristics) in order to get something that is ideal. What GC grows 6" height and is pretty there?

I see you have underground sprinklers. If you do ground cover will it get watered each time the lawn is watered?
If so I would like to tell you some GC not to get.
Hypericum calycinum, Oenothera speciosa, Hedera..They can be thugs with regular watering.