As the title. I cannot find anything on that.
Spitual Ally:
The spiritual ally occupies its space, though you and your allies can move through it, since it is your ally. The spiritual ally carries a single weapon, one favored by your deity (as for spiritual weapon), which has the same threat range and critical modifiers as a real weapon of its form. Each round on your turn, starting with the turn that you cast this spell, your spiritual ally can make an attack against a foe within its reach that you designate. The spiritual ally threatens adjacent squares and can flank and make attacks of opportunity as if it were a normal creature. The spiritual ally uses your base attack bonus (gaining extra attacks if your base attack bonus is high enough) plus your Wisdom bonus when it makes a melee attack. When the spiritual ally hits, it deals 1d10 points of force damage + 1 point of damage per 3 caster levels (maximum +5 at 15th level). It strikes as a spell, not a weapon, so it bypasses DR and can affect incorporeal creatures.
Each round after the first, you can move the spiritual ally as a swift action. It has a speed of 30 feet, and a fly speed of 30 feet (perfect maneuverability). Being a construct of force, the spiritual ally cannot be harmed by any physical attacks, but dispel magic, disintegrate, a sphere of annihilation, or a rod of cancellation affects it. A spiritual ally's AC against touch attacks is 10.
If an attacked creature has spell resistance, you make a caster level check (1d20 + caster level) against that spell resistance the first time the spiritual ally strikes it. If the ally is successfully resisted, the spell is dispelled. If not, the weapon has its normal full effect on that creature for the duration of the spell.
Since it is not in the description, it cannot. It is merely an upgrade to Spiritual Weapon (a good one).
Ok, just what I thought. A friend of mine, who plays a cleric (with an atonishing 26 wis, 10th level), is not so happy with this spell. He says that he'd prefer to make a combat maneuver instead of simply do damage. It has some point, as we're a magus and a paladin who do a lot of damage, but I find that spell rather good. He's mainly an healer (and saved our lives countless times), and he don't do frontline action. He buffs and heal. So, he wanted to know to decide for a 5th level spell.
As Eltacolibre says.
Since your cleric seems to want pro-active battlefield control - which is always a good idea - the summons are the only way. For passive control he has Wall of Stone.
The Ally provides an indestructible source of damage and a flanking buddy, with advantages against DR and incorporeal things, but nothing more.
(With 26 WIS he could look into Soundburst + Dazing Spell, which is a nice control effect for a spell.)
Alzo he can use toppling spell with spiritual ally to send the bad guys sprawling.
Nice suggestions, thanks. He started almost only as healer (he's a youg guy at his first campaign), but he evolved to be useful in other way aside healing. He has the classic low level buffs (prayer, bless), and he was looking for a more incisive way. Unfortunately, he doesn't have any metamagic feat, and the campaign will end at 13th. Maybe I suggest him to take some metamagic...