What’s developing

• Mobility toward pull-to-stand and cruising; balance improves on each child’s timeline.
• Hand accuracy—lining pieces to a hole/outline gets easier.
• Cause–effect—press → pop, post → drop, roll → reappear.
• Short focus + brief wait for a reveal.
• Turn-taking + imitation (“you do one, I do one”).
• Mouthing—safe materials and easy cleaning still matter.

How to pick

1. Easy to hold: one-handable, no fiddly alignment.
2. Instant feedback: mechanical actions over lights/songs.
3. Quick win first: single-action loop (place→in / press→pop / roll→out), then add difficulty.
4. Easy to clean & put away: washable, no water traps; one bin to reset.
5. Upgradeable: same toy scales (slot width, piece count, distance).

The Lean Four

Keep these within reach. If you’ll buy one item first, choose a posting box with a swap-top shape lid and put out only 1–2 shapes at a time.

• Posting box + large discs. Take turns—“you one, me one”—then tip out and repeat. Upgrade when baby posts several in a row without looking (≈6–8); narrow the slot or add color/number rules. If stuck: park the disc at the rim; use larger, thicker discs.
• Object permanence (“find-the-ball”) box. Roll in, pause a beat, then find it together. Upgrade when there are a few back-to-back finds (≈3); switch to a cardboard ramp/longer path. If stuck: demo the exit once.
• Pounding bench. Palm-press counts as success; then gentle taps with a light, short, rounded mallet. Upgrade when gentle taps are steady; tighten pegs a little or alternate hands. If stuck: two-finger presses or “one soft tap, short pause.”
• Chunky knob puzzle (1–2 pieces). Place the piece on the outline edge and let baby push it in. Upgrade when 1–2 pieces are instant; move to three or irregular outlines. If stuck: the board may simply be too tight—swap it.

Quick-start play

1. Put three large discs on a mat or tray. Take turns—“you one, me one”—for two rounds.
2. Roll a ball into the find-the-ball box, pause briefly, then “find it” twice.
3. Tidy together: sweep discs into the bin while counting.
4. Quiet/tight spaces: soft ball + cardboard ramp; hand-press instead of mallet; one puzzle piece and end on a win.

When play stalls

1. Lower the load: fewer pieces, shorter distance, simpler action.
2. Change the start: move the piece close to the target; baby finishes the last step.
3. Change the field: if throwing persists, switch to a soft-ball “basket”; still intense—take it outdoors, then reset.

Rotation & tidy

• Keep 5–7 items out (Lean Four + 1–3 regulars/subs); rotate every 3–4 days.
• Two-bin reset: one “out now,” one “on deck.” Swap on rotation days; evenings = toss today’s toys back in the “out” bin.
• Toy island: tape a 60–80 cm circle on the floor; toys live inside. End with “toys go home” and count while tidying.

These simple rotations keep the best toys for 9–12 month old babies feeling fresh without buying more.

Home substitutes

• Smooth edges first: cut large, slightly thick cardboard discs for posting.
• Cardboard posting/drawer box/ramp (tape edges smooth).
• Cutting board as a press-and-pound base; soft block as a “mallet.”
• Sofa/coffee-table edge as a cruising rail (add corner guards).

Keep using these (carryovers)

• Stacking cups: pour/transfer with water; hide-and-find a small ball. Upgrade: “fill before pour.”
• Ring stacker: try horizontal posting; limit to two colors; “pick first, then post.” Upgrade: increase distance a little.
• Mechanical pop-up: press then wait a beat; take turns; vary button order. Upgrade: two-step sequence, then three.
• Large soft ball: add a finish line; roll–chase–return for three rounds; try basket-to-cushion. Upgrade: move the line back.
• Cloth/flap books: point-and-name; pause on each page. Upgrade: prompt-only (“Where’s the puppy?”).
• Soft/wood blocks: build 2–3 levels; tape “parking bays” and push cars into the grid. Upgrade: try a bridge/door shape.

Quick cautions

• Too-tight shape sorters create frustration—swap the box, not the child.
• Tiny linking beads/strong magnets—skip, or choose oversized, well-sealed versions only.
• Bath squirt toys trap water—buy sparingly or skip; choose open, quick-drain designs.
• Heavy, long mallets are noisy and risky—palm-press first, then light taps.

Safety & cleaning

• Size feel: use larger, thicker discs and balls (roughly ≥1.75 in / 4.4 cm diameter); supervise mouthing.
• Small parts & magnets: avoid strong magnets, loose small pieces, and accessible button batteries.
• Walker note: skip sit-in walkers; consider push toys later—once pull-to-stand/cruising—choose low center of gravity with addable weight/adjustable resistance.
• Cleaning: daily quick wash/dry for mouthables; surface-wipe battery toys; screw-secured battery doors are best.

Save this guide to the best toys for 9–12 month old babies and come back as you upgrade difficulty.

Further reading: Baby’s First Foods · Best Toys for 6–9 Month Old Babies · AAP: Infant Walkers—A Dangerous Choice · NHS: Your baby at 9 to 12 months